Cell controller, battery module and power supply system

ABSTRACT

A cell controller with excellent reliability in which noise and soon are suppressed is provided. The cell controller includes, corresponding to the number of cell packs, a plurality of ICs each having a voltage detecting circuit detecting voltages of respective cells of a cell pack in which four cells are connected in series, a switch control circuit controlling conduction and a blocking operation of a plurality of switch elements connected in parallel to the respective cells via capacity adjusting resistors, a LIN1 terminal for inputting control information, a LIN2 terminal for outputting control information, a Vcc terminal and a GND terminal, and a LIN2 terminal of a higher-order IC and a LIN1 terminal of a lower-order IC are connected in a daisy chain. The Vcc terminal of each IC is connected to a positive electrode of a higher-order cell among cells constituting a corresponding cell pack via an inductor L for eliminating noise, and the GND terminal is coupled directly to the Vcc terminal of the lower-order IC. Noise is not superposed on the LIN1, LIN2 terminals.

FIELD OF THE INVENTION

The present invention relates to a cell controller, a battery module anda power supply system, and more particularly relates to a cellcontroller for controlling a serially connected body of cells in which aplurality of cells are connected in series, a battery module includingthe cell controller, and a power supply system including the batterymodule.

DESCRIPTION OF THE RELATED ART

Conventionally, for example, as a power supply for charging/discharginglarge current for a hybrid electric vehicle (HEV) which is driven by anengine and a motor or an electric vehicle such as a pure electricvehicle (PEV) which is driven only by a motor, it has been used abattery module including a serially connected body of cells including aplurality of cells such as nickel hydride secondary cells, lithiumsecondary cells, or the like connected in series.

A cell controller mounted in a vehicle, a battery module including thecell controller, and a power supply system including the battery modulehas a possibility to be used in various environments for a long period,and it is an important problem to be capable of maintaining highreliability even when being used in a harsh environment.

Note that as background arts related to the present invention, there aredisclosed a technique to construct a battery module by connecting alarge number of cells (for example, refer to Japanese Patent ApplicationLaid-open No. H10-270006), and a technique to have a plurality of ICscorresponding to the number of battery units and perform transmission ofinformation in a daisy chain between the ICs (for example, refer toJapanese Patent Application Laid-open No. 2003-70179, Japanese PatentApplication Laid-open No. 2005-318750, Japanese Patent ApplicationLaid-open No. 2005-318751).

SUMMARY OF THE INVENTION

A problem to be solved by the present invention is to provide a cellcontroller, a battery module or a power supply system which haveexcellent reliability, or to improve reliability of an on-vehiclesystem. Note that in an embodiment described below, various problems canbe solved besides the above-described problem. These problems and meansfor solving them will be described in detail in the embodiment.

A cell controller to which the present invention is applied includes,corresponding to groups, a plurality of ICs each having a voltagedetecting unit detecting voltages of respective cells constituting thegroups, a switch control unit controlling conduction and a blockingoperation of a plurality of switch elements connected in parallel to therespective cells via resistors, an information input terminal forinputting control information, an information output terminal foroutputting control information, a power supply terminal (hereinafterreferred to as Vcc terminal) and a reference potential terminal(hereinafter referred to as GND terminal), and an information outputterminal of a higher-order IC and an information input terminal of alower-order IC are connected in a daisy chain. The Vcc terminal of eachIC is connected to a positive electrode of a higher-order cell amongcells constituting a corresponding group via a first inductor foreliminating noise. Such a cell controller is also used for a batterymodule and a power supply system.

According to the present invention, a highly reliable cell controller,battery module including the cell controller, and power supply systemincluding the battery module or a highly reliable on-vehicle systemusing them can be obtained.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exterior perspective view of a battery module included in apower supply system of an embodiment to which the present invention isapplicable;

FIG. 2 is a perspective view showing an assembly state of an upper coverof a battery module;

FIG. 3 is a perspective view showing an assembly state of a cell packblock in which cell packs are assembled;

FIG. 4 is an exterior perspective view of the cell pack block;

FIG. 5 is an exploded perspective view of lower cover components of thebattery module;

FIG. 6 is a schematic cross-sectional view of the battery moduleschematically showing distribution paths of cooling air;

FIG. 7 is an exterior perspective view of the cell pack;

FIG. 8 is an exterior perspective view of cylindrical lithium secondarycells constituting the cell pack;

FIG. 9 is a plan view schematically showing a substrate constituting acell controller, partially including a perspective view;

FIG. 10 is a circuit diagram of the cell controller;

FIG. 11 is a circuit diagram of a protection circuit inside ICsconstituting the cell controller;

FIGS. 12(A) to 12(D) are explanatory diagrams of a cell controller inwhich a GND terminal of a higher-order IC and a Vcc terminal of alower-order IC are connected via an inductor, and a LIN2 terminal of thehigher-order IC and a LIN1 terminal of the lower-order IC are coupleddirectly, FIG. 12(A) showing a circuit diagram, FIG. 12(B) showing avoltage waveform of noise of 60 Vpp, FIG. 12(C) showing a voltagewaveform of noise superposed between the GND terminal and the LIN1terminal, and FIG. 12(D) showing a voltage waveform of noise superposedbetween the GND terminal and the Vcc terminal;

FIGS. 13(A) to 13(D) are explanatory diagrams of a cell controller of anembodiment, FIG. 13(A) showing a circuit diagram, FIG. 13(B) showing avoltage waveform of noise of 60 Vpp, FIG. 13(C) showing a voltagewaveform of noise superposed between the GND terminal and the LIN1terminal, and FIG. 13(D) showing a voltage waveform of noise superposedbetween the GND terminal and the Vcc terminal;

FIG. 14 is an explanatory diagram of a voltage applied to the LIN2terminal in the cell controller in which the LIN2 terminal of thehigher-order IC and the LIN1 terminal of the lower-order IC are coupleddirectly;

FIG. 15 is an explanatory diagram of a voltage applied to a CV3 terminalof an IC constituting a cell controller during assembly;

FIG. 16 is an exterior perspective view showing a fixed state of thebattery module in the power supply system;

FIG. 17 is a block circuit diagram showing a driving system of avehicle; and

FIG. 18 is a block circuit diagram of a voltage detecting circuit in anIC.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A cell controller for mounting on a vehicle or a battery moduleincluding the cell controller or a power supply system including thebattery module, which will be explained in an embodiment below, has aneffect of improving reliability, but achieves not only this effect butalso other effects. More specific effect regarding the improvement ofreliability or effects other than the improvement of reliability whichthe embodiment below has will be explained next.

[Improvement of Reliability]

The cell controller for lithium secondary cells or the battery moduleincluding the cell controller or the power supply system including thebattery module, which will be explained below, can obtain large effectsin terms of improvement of reliability. A rotary electrical machinemounted in a vehicle requires large electrical power. Also, anon-vehicle power supply is required to be made smaller or lighter.Lithium secondary batteries which are small and capable of providinglarge electrical power are expected largely as on-vehicle power supply.

It is conceivable that a lithium secondary battery mounted in a vehicleis used as power supply for a rotary electrical machine for driving avehicle or for a rotary electrical machine for power steering. As atypical on-vehicle rotary electrical machine, there are synchronouselectric motors using a permanent magnet or induction motors having acage-type rotor. For driving any one of these rotary electricalmachines, an inverter device is necessary, which performs powerconversion between direct current power and alternate current power. Theinverter device performs the aforementioned conversion between directcurrent power and alternate current power by a switching operation of apower switching element such as an IGBT or a MOS transistor constitutinga bridge circuit. By this switching operation, large noise is generatedand affects the direct current power supply system. The cell controllerfor lithium secondary cells or the battery module including the cellcontroller or the power supply system including the battery module,which will be explained later as an embodiment, exhibits a large effectin terms of improvement of reliability in the on-vehicle system usingthe aforementioned inverter device for power conversion.

Further, the inverter device normally has a smoothing capacitor foreliminating noise generated by the inverter device. For eliminating theaforementioned noise, it is desirable to increase the capacity of thesmoothing capacitor. However, thorough elimination of noise leads toincrease in size of the aforementioned smoothing capacitor, and alsoleads to increase in size and cost of the device. Therefore, it isdesirable that the direct current power supply system itself becomestough against noise. Further, the capacitor, particularly anelectrolytic capacitor has a problem in temperature characteristics ofthe capacitor such that the capacity decreases at a low temperature. Theon-vehicle power supply is used in an environment where the temperaturechanges frequently. It is desirable that the on-vehicle power supplyexhibits a sufficient ability even in an environment where thetemperature changes from minus 30° C. or minus 40° C. to nearly 100° C.for example. The capacitor has a possibility of decrease in ability as acapacitor when the temperature lowers. The electrolytic capacitor inparticular has large characteristics deterioration. Accordingly, in alow temperature state, with a temperature of minus 10° C. or lower forexample, the ability as a smoothing capacitor decreases rapidly. Thecell controller for lithium secondary cells or the battery moduleincluding the cell controller or the power supply system including thebattery module, which will be explained later as an embodiment, canmaintain high reliability also against deterioration of a noiseelimination characteristic due to characteristics deterioration of thecapacitor.

Nickel hydride batteries have large decrease in ability at a lowtemperature, for which control that can suppress supplied power at a lowtemperature is considered. Accordingly, the influence of noise tocharacteristics deterioration of the capacitor at a low temperature isnot taken as a problem so much. However, lithium secondary batteries areexcellent in characteristics at a low temperature than the nickelhydride batteries, and it is conceivable to use a lithium secondarybattery at a low temperature. Accordingly, a cell controller or the likethat can endure increase in influence of noise due to deterioration oflow temperature characteristics of the capacitor is desired. Theembodiment described below has an effect to suppress such increase ininfluence of noise.

When a lithium secondary battery is used as an on-vehicle direct currentpower supply, a large number of lithium secondary cells as cells areconnected in series, and it is necessary to control charge/dischargestates of the cells (unit cells) connected in series respectively withhigh accuracy. Accordingly, it is necessary to reduce imbalance incharge/discharge states of the cells by detecting a terminal voltage ofeach cell. In the embodiment which will be described later, for reasonssuch as simplification of the system and reduction in price, a detectioncircuit for the terminal voltages of the cells, a control circuit forreducing the imbalance in charge/discharge states, and a switchingcircuit performing conduction or blocking of a discharge current aremade by an IC. A plurality of such ICs are used in combination to enablecontrol to reduce imbalance in charge/discharge states of cellsconstituting the lithium secondary battery. According to thisembodiment, other than the above-described operation and effect, thereis further an effect to improve reliability in control of thecharge/discharge states of the cells connected in series. Further, thereis an effect to realize this control by a relatively simple circuitstructure. As a result, realization of reduction in price becomes easy.

In the embodiment below, the ICs operate by power supplied from thecells, which are targets of detecting a terminal voltage, and the ICshave different reference voltages. Control informationtransmitted/received to/from the ICs is transmitted via a looptransmission path constituted of the ICs connected in order of thelevels of reference voltages, and by this loop transmission,transmission/reception to/from the ICs are performed. In the cellcontroller or the battery module including the cell controller or thepower supply system including the battery module in which the looptransmission path is thus formed by the ICs, noise generated by theinverter device, which is applied to a direct current power outputterminal of the lithium secondary battery module enters the ICs not onlyfrom the detection circuit for terminal voltages of the cells butthrough the loop transmission path, there is a concern of giving aninfluence that leads to malfunction or circuit destruction. A circuitdescribed as an embodiment which will be explained below can reduceinfluence of noise via the aforementioned loop transmission path, andhas an effect to be capable of maintaining high reliability other thanthe above-described effects.

In a nickel hydride secondary battery and a lithium secondary battery,it is desirable to detect terminal voltages and perform management ofcharge/discharge states of cells or the like. In the nickel hydridesecondary battery, terminal voltages are detected by dividing intoblocks. In the lithium secondary battery, all terminal voltages of cellsare detected and charge/discharge states are managed so that all thecells will not be overcharged. For simplifying connecting operation, inthe embodiment described below, a large number of lines for detectingterminal voltages of cell blocks or cells constituting a battery are ledto the cell controller and connected to the circuit of the cellcontroller with connectors. The aforementioned connectors are connectedto the circuit of the cell controller in a state that terminal voltagesof the battery block or the cells constituting the battery are appliedthereto, and during the connecting operation, there exists a state thatpart of terminals of the connectors are connected partially. Once theconnectors are connected completely, a planned voltage is applied to thecircuit of the cell controller, but when only part of the connectors areconnected, it is possible that an abnormal voltage is applied thereto.

Particularly in a lithium secondary battery, a wiring for detecting aterminal voltage is necessary between terminals of each cell and thecell controller, which results in that the connectors have a largenumber of connecting pins. Accordingly, when the connectors areconnected or released, it is highly possible that a partial connectionoccurs in which only a part of the connectors is connected. Theembodiment explained below has an effect to be capable of protecting acircuit such as the cell controller against damage due to application ofan abnormal voltage even when the partial connection in which only apart of the connectors are connected occurs, other than theabove-described effects. Also, in the embodiment explained below, thereare provided a plurality of connectors, in which connectors forconnecting terminals of cells on a high potential side to the circuit ofthe cell controller and connectors for connecting terminals of cells ona low potential side to the circuit of the cell controller areseparated. This enables lowering of abnormal voltage applied to thecircuit of the cell controller when pins of the connectors are connectedpartially, and the influence of the above-described partial connectionof the connectors can be reduced further. Moreover, the embodimentfurther has an effect to be capable of protecting the circuit of thecell controller by providing a diode or the like for protecting an IC atan appropriate position as will be explained below.

[Uniformization of Power Consumption of Cells]

Other than the above-described effects, in the embodiment below, thefollowing improvements are made for uniformizing power consumption ofthe cells connected in series as much as possible, and there is aneffect to reduce imbalance of charge/discharge states of the cells. Whenthe charge/discharge states of the cells can be uniformized, apossibility that only a certain cell is overcharged becomes low in acharging operation of the cells connected in series, and thereby safetyand reliability of the entire module battery improve.

The cells connected in series are divided in groups, ICs are providedcorresponding to the groups, and each IC operates by power from cellsconstituting a corresponding group. By uniformizing the number of cellsconstituting each group as much as possible, there is an effect that thecells connected in series can bear the power consumed by the ICs as evenas possible, and there is an effect that imbalance of charge/dischargestates of the cells can be reduced.

Also, the ICs receive a power supply voltage from a battery terminal(electrode of the battery) having a highest voltage in a correspondinggroup and operates with a battery terminal (electrode of the battery)having a lowest voltage in the aforementioned group being a referencepotential. With this structure, the power required for the ICs tooperate is shared evenly among the cells in the corresponding group,thereby providing an effect that imbalance in charge/discharge states ofthe cells can be reduced.

Signal transmission as an important function of the ICs is performed viaa loop constituted by all the ICs. Accordingly, the power consumed bytransmission of a signal becomes uniform among the ICs. Even iftransmission/reception between part of the ICs and the aforementionedcontrol device increases, the transmission of a signal passes all theICs, thereby providing an effect that the power consumption isuniformized. Further, the embodiment below has a structure in whichpower required for each IC to operate is obtained from all the cellsconstituting the group to which this IC corresponds to, therebyproviding an effect that the imbalance in charge/discharge states of thecells constituting the secondary battery can be reduced.

In the embodiment below, a LIN12 terminal is provided in each IC forcorresponding to a load having large power consumption. The load havinglarge power consumption is, for example, a photo transistor operating athigh speed. When the IC transmits/receives a signal to/from the loadhaving large power consumption, a large current can be provided to theaforementioned load from the LIN12 terminal. On the other hand, an ICconnected to a load having small power consumption can originallyperform an operation of transmission/reception of a signal preciselyeven when the LIN12 terminal is released, but in the embodiment below,the aforementioned LIN12 terminal is connected to a terminal fortransmitting/receiving a signal between adjacent ICs, for example a LIN2terminal for transmission. Each IC is made to operate precisely evenwhen a current of the aforementioned LIN12 terminal flows. Theembodiment below has a structure to uniformize the power consumption ofthe ICs as much as possible by thus providing the LIN12 terminal for aload having large power consumption, and connecting the LIN12 terminalto the transmission/reception terminal of each IC even when a loadhaving large power consumption is not present. Therefore, in theembodiment below, there is an effect that power consumption of the ICsis balanced as much as possible, which is an effect other than theabove-described effects. By balancing the power consumption of the ICs,there is an effect that the power consumption of the cells connected inseries is balanced.

Hereinafter, an embodiment of applying the present invention to anon-vehicle power supply system will be described with reference to thedrawings. The following embodiment is explained as examples of applyingthe present invention to a power supply system for a hybrid vehicle, butas a matter of course, the embodiment can also be applied to a pureelectric vehicle which runs only by torque of a rotary electricalmachine instead of hybrid drive, in other words, instead of a structureto run a vehicle directly by torque of an engine.

(Structure)

The power supply system of this embodiment has two stacked batterymodules which constitute a high voltage battery. As shown in FIG. 1 andFIG. 2, a battery module 9 has a module case 9 a in a substantiallyrectangular parallelepiped shape, which is made of metal and constitutedof an upper cover 46 and a lower cover 45. In the module case 9 a, aplurality of cell packs 19 are accommodated and fixed. The batterymodule 9 is covered by the module case 9 a which is a metal case, and inthe module case 9 a, a large number of wirings for detecting voltage,temperature and so on exist, but they are protected against electricalnoise from the outside. Further, as described above, the cells areprotected by the module case 9 a and a container on the outside thereof,and thereby safety of the power supply system will be maintained even ifa traffic accident occurs.

<<The Cell Packs>>

As shown in FIG. 7, in a cell pack 19, a plurality of (four in thisembodiment) cells 10 are arranged in two lines and two rows to havealternating polarities, and the plurality of, preferably four, cells 10are connected in series. Although there are various types of shapes ofcells, cylindrical lithium secondary cells each covered by a casinghaving high heat conductivity are used as cells in this embodiment asshown in FIG. 8, with positive electrode active material being lithiummanganese complex oxide and negative electrode active material beingamorphous carbon. These cells of lithium secondary cells have a nominalvoltage of 3.6 V and a capacity of 5.5 Ah, but terminal voltages of thecells change as charge states change. When charge amounts in the cellsdecrease, the terminal voltages decrease to about 2.5 volt, and whencharge amounts in the cells increase, the terminal voltages increase toabout 4.3 volt.

In this embodiment, the cells 10 are integrated as the cell packs 19with a positional relationship such that side faces thereof oppose eachother, and these cell packs 19 are fixed inside the module case 9 a withan arrangement relationship such that the side faces of the cells opposeeach other as shown in FIG. 6. This arrangement relationship isexcellent for improving productivity. Moreover, such a structuresimplifies the connecting operation of a detection harness 52, a highvoltage cable 35, and so on, which will be explained below using FIG. 3to FIG. 6, and thereby the safety can be maintained further.

As shown in FIG. 7, a cell pack 19 is constituted such that two holders11 constituted of resin moldings having high electrical insulativeproperty sandwich cells 10 in a vertical direction with respect to thecircumferential direction of the cells 10, namely a longitudinaldirection of the cells, and four cells 10 are connected electrically inseries by being spot welded with metal bus bars with each other.Further, to the cell pack 19, voltage detecting lines 58 (refer to FIG.10) for detecting voltages of the cells 10 and adjusting the voltages(capacity as a charge/discharge state of the cells 10) are connected.The metal bus bars are gathered on one of the holders 11 (the left sideone shown in FIG. 7) via a not-shown flexible substrate constituting thevoltage detecting lines 58. For improving workability, the metal busbars and the not-shown flexible substrate are connected in advancebefore assembly of the cell pack 19. In other words, a plurality ofconducting lines constituting the voltage detecting lines 58 areprint-coated on the flexible substrate, with one ends of the conductinglines being connected to the metal bus bars, and the other ends thereofbeing gathered to a connector.

Also, the cells 10 are held (fixed) by holders 11 so that externalterminals are located on a side face of the cell pack 19. By arrangingthe cells 10 so that the circumferential faces of the cells oppose eachother, the cell pack 19 is constructed compactly. Further, the cells 10are arranged such that the external terminals of the four cells 10connected in series are arranged regularly in the same direction (referto numerals 12, 13). Such an arrangement and a structure enable tomaintain safety in addition to improvement of workability, and are alsofavorable in an aspect of maintenance. Shock resistance in a state ofbeing mounted in a vehicle also improves, and it is also favorableagainst mechanical shock in a traffic accident of a vehicle.

As shown in FIG. 3 to FIG. 7, at two vertical positions between theholders 11, arch-shape louvers 36 are arranged respectively, whichdefine the distance between the holders 11 and have a U-shape crosssection for allowing distribution of cooling air on the outercircumferential face sides of the cells 10. Further, at the centerbetween the holders 11, a cross-shape louver 37 is arranged, whichdefines the distance between the holders 11 and has a cross-shapecross-section for allowing distribution of cooling air on innercircumferential face sides of the cells 10 (refer to FIG. 6). Note thata part of the flexible substrate is fixed to the cross-shape louver 37along a longitudinal direction of the cross-shape louver 37 to the sideof the other holder 11 (on the right side shown in FIG. 7) opposite tothe one holder 11 to which the connector is fixed. A vehicle in whichthe power supply system of to this embodiment is mounted will be usedunder various severe environmental conditions. The above-describedstructure of distributing the cooling air can suppress increasing oftemperature while being used under severe environmental conditions, andis excellent in terms of realizing both size reduction and efficientcooling of an apparatus.

On one of the holders 11, an inter-cell bus bar 39 for connecting thecells 10, a positive electrode bus bar 12 for a positive electrodeoutput, and a negative electrode bus bar 13 for a negative electrodeoutput are insert molded. Further, nuts for fastening by screws areinserted in the positive electrode bus bar 12 and the negative electrodebus bar 13. Also, on the other holder 11, two inter-cell bus bars areinsert molded in a direction crossing the inter-cell bus bar 39.Therefore, by spot welding these bus bars and the cells 10, the cellpack 19 in which four cells 10 are connected in series can beconstructed. Note that as will be described later, temperature sensorsTH1 to TH4 (refer to FIG. 10) such as thermistors are attached to cells10 constituting a certain cell pack 19, and from this cell pack 19,detecting lines 58 from the temperature sensor are also led out besidesthe voltage detecting lines 58 and gathered to the connector thereof.

The above-described structure of the cell pack and arrangementrelationship of the voltage and temperature detecting lines 58 areexcellent in workability, and also excellent for size reduction of anentire apparatus. Also, the cell pack with this structure can becommonly used in other types of power supply systems, which results inimprovement of productivity. Further, the structure is also excellent inwelding workability for cells, and since electrical connection is madeby welding operation, an electrical connection state can be maintainedfavorably for a long period of time. Therefore, safety and reliabilitywith respect to mechanical vibration and shock are maintained eventhough high current flows therein.

<<Cell Pack Blocks>>

As shown in FIG. 3 and FIG. 4, in this embodiment, for improvingassembly performance and convenience in handling of the battery module9, a plurality (six in this embodiment) of cell packs 19 are arranged ontwo channel-shape block bases 41, which each have a substantiallyh-shape cross-section and are arranged so as to oppose each other, andare fixed with tapping screws 42 engaging with fixing holes (femalescrew parts) formed in the holders 11. Thus a cell pack block 40 isassembled, in which a serial connection is made by inter-cell pack busbars, which fasten the negative electrode bus bars 13 and the positiveelectrode bus bars 12 of adjacent cell packs 19 with each other.Therefore, workability for the structure to fix a plurality of cellpacks 19 to the block bases 41 in parallel improves. Also, productivityof the cell packs 19 improves, thereby enabling a structure anddimensional relationship in common with cell packs in other power supplysystems. The cell pack block is also excellent for detection of cellsfor quality management and for maintenance after production.

As shown in FIG. 3, the block base 41 has a plurality of flanges 43 and44 projecting from side faces thereof to laterally fix the cell packblock 40 to the lower cover 45 (refer to FIG. 5). There are two types ofthese flanges, and for convenience, ones located on the outside of thebattery module 9 are referred to as block flanges 43, and ones locatedon the inside thereof are referred to as block flanges 44. In otherwords, when it is assumed that a face located on the outside of thebattery module 9 is a face to which the connector of the cell pack 19 isfixed, the block flanges 43 are disposed on the block base 41 on thisface. The block flanges 43 are sandwiched by the lower cover 45 and theupper cover 46 (refer to FIG. 2 and FIG. 6), and the block bases 41 arefastened and fixed simultaneously as fastening of the lower cover 45 andthe upper cover 46 (also refer to FIG. 2). Also, on both ends of theblock bases 41, block base circular holes 47 are formed for fixing thecell pack block 40 on the lower cover 45 from front and back sides. Sucha structure or arrangement is excellent in workability and productivity.

As shown in FIG. 4, on an upper part of the cell pack block 40, blockreinforcing plates 51 having a substantially L-shape cross section and achannel shape are arranged in parallel with the block bases 41. The cellpacks 19 are fixed laterally to the block reinforcing plates 51 from afront face side and a rear face side by tapping screws 42. On the blockreinforcing plate 51 on the side where the connector is fixed, adetection harness 52 is fixed, which is connected to the voltage andtemperature detecting lines 58 of the respective cell packs 19constituting the cell pack block 40. Specifically, cable ties 55 forattaching tie bands 54 are fixed to one of the block reinforcing plates51 by the tapping screws 42, and the detection harness 52 is fixed tothe block reinforcing plate 51 by the tie bands 54. Further, the blockreinforcing plates 51 have block reinforcing plate curving portions 56curving at two positions and have circular holes formed therein. Hooksmade of thick wire are inserted in these circular holes for handling,such as carrying the cell pack block 40. With this structure, strengthof the cell pack blocks 40 constituted by fixing a plurality of cellpacks 19 increases. Also, mechanical strength is maintained againstvibration and shock with respect to the detection harness 52 connectedto the voltage and temperature detecting lines 58 of the respective cellpacks 19, and further, the structure is excellent in workability forelectrical connection.

<<Battery Module>>

As shown in FIG. 5, the lower cover 45 is constituted of six types ofparts: a lower cover base 61, a (cooling air) introducing side fixingtable 62, a (cooling air) discharging side fixing table 63, block fixingbases 64, a reinforcing louver 65, and center poles 66.

The lower cover base 61 constitutes a front face, a bottom face, and aback face of the module case 9 a. On a front face portion of the lowercover base 61, circular holes for taking out a positive electrode highvoltage cable 81 and a negative electrode high voltage cable 82 (referto FIG. 2) are formed respectively on both sides of the center thereof,and on a lower side thereof, a slit-shape intake 14 for introducingcooling air is formed. Further, an upper face side and side ends of leftand right side faces of the front face portion of the lower cover base61 are bent in an L shape. On the other hand, on a lower side of a backface portion of the lower cover base 61, a slit-shape exhaust port 15for exhausting cooling air is formed at a position corresponding to theintake 14 formed in the front face portion (refer to FIG. 1, FIG. 6).From a bottom face portion of the lower cover base 61, lower coverflange portions 68 are extending outward laterally from the left andright sides, which are located higher than the bottom face of the lowercover base 61 and have a substantially horizontal face. On end portionsof the lower cover flange portions 68, bent ribs 69 which are bentupward are formed respectively.

On the front face portion side of the bottom face portion of the lowercover base 61, the introducing side fixing table 62 for fixing the blockbases 41 of the cell pack block 40 from the front face side, and guidingthe cooling air introduced from the intake 14 to the reinforcing louver65 is fixed (also refer to FIG. 6). On the other hand, on the back faceportion side of the bottom face portion of the lower cover base 61, thedischarging side fixing table 63 are fixed for fixing the block bases 41of the cell pack block 40 from the back face side, and guiding thecooling air distributed through the battery module 9 to the exhaust port15 via two discharge ports 72 formed in an upper face thereof (alsorefer to FIG. 6). Also, along the center in a longitudinal direction ofthe bottom face portion of the lower cover base 61, the center poles 66(also refer to FIG. 2) for supporting a center portion in thelongitudinal direction of the upper cover 46 and coupling (fastening byscrews) to the upper cover 46 and the block fixing bases 64 for fixingthe block flanges 44 of the block base 41 of the cell pack block 40 arefixed alternately. With this structure, an excellent coolingcharacteristic can be obtained despite that the entire shape has arelatively small size.

Further, on the lower cover base 61, the reinforcing louver 65 is fixedfor reinforcing strength of the bottom face of the lower cover base 61and for supplying cooling air to each of the cell pack blocks 40. Thecenter in a longitudinal direction of the reinforcing louver 65 is incontact with the bottom face portion of the lower cover base 61, andcircular holes and rectangular holes for inserting the center poles 66and the block fixing bases 64 fixed to the lower cover base 61 areformed therein. Both sides sandwiching the center in the longitudinaldirection of the reinforcing louver 65 are one step higher (hereinafter,these portions are referred to as duct forming portions), and theseportions forms with the lower cover base 61 ducts 75 having arectangular-shape opening cross-section. In the duct forming portions ofthe reinforcing louver 65, rectangular ventilation holes 76 are formedat positions corresponding to positions between the cells 10constituting the cell packs 19 (also refer to FIG. 6). A substantiallyhalf of an opening area of the closest ventilation hole to the intake 14is covered by a rib-shape blocking louver 77 which inclines obliquely.With the above-described structure, an excellent cooling effect can beobtained with a small number of parts.

Both lateral sides of the duct forming portions of the reinforcinglouver 65 are, similarly to the center in the longitudinal direction, incontact with the bottom face portion of the lower cover base 61. Ends onboth lateral sides of the reinforcing louver 65 stand up, and furtherthe flange portions having a substantially horizontal face extendoutward laterally from the left and right sides. The flange portions ofthe reinforcing louver 65 are in contact by surface with the lower coverflange portions 68 of the lower cover base 61 and fixed thereon. Also,the reinforcing louver 65 is cut out in the front face and back faceportions so as to avoid positions of the introducing side fixing table62 and the discharging side fixing table 63 fixed to the lower coverbase 61. Note that an end on the introducing side fixing table 62 sideof the duct forming portions of the reinforcing louver 65 is inserted inthe introducing side fixing table 62 so that the ducts 75 communicatewith the intake 14 (also refer to FIG. 6). With such a structure and aconfiguration, an excellent cooling characteristic can be obtained.

As shown in FIG. 2 and FIG. 3, two cell pack blocks 40 are fixed inparallel on the lower cover 45. Specifically, stud bolts 78 (refer toFIG. 5) formed to stand on the introducing side fixing table 62 and thedischarging side fixing table 63 are inserted in the circular holes 47on the both ends of the block bases 41 of the respective cell packblocks 40, and are fixed by nuts including springs. Also, the blockflanges B44 of the block bases 41 of the cell pack block 40 are fixedtogether by nuts including springs so as to oppose each other on theblock fixing bases 64. By disposing two cell pack blocks in parallel,the entire battery module becomes relatively small.

In FIG. 6 and FIG. 9, on the discharging side fixing table 63, a cellcontroller box (C/C box) 79 including a cell controller (hereinafter,abbreviated to C/C) 80 shown in FIG. 9 is fixed to the lower cover base61 (refer to FIG. 5) by screws. As shown in FIG. 9, the C/C 80 isconstituted of a single substrate which is laterally long and hasprinted wirings on both faces, and is fixed in a standing state byscrews via circular holes formed at four respective vertical positionsinside the C/C box 79. The substrate having ICs is arranged in arelationship to oppose side faces of the cells constituting the cellpacks, and with such a structure, the entire module can be accommodatedin a relatively small space. Also, complexity in wirings of therespective cell packs and the C/C 80 can be eliminated.

Connectors 48, 49 for connecting to the cells constituting the batteryblock 40 via the detection harness 52 are provided on ends on both leftand right sides of the substrate constituting the C/C 80 with a distancetherebetween. A harness connector (not shown in FIG. 4) attached to oneside, which is the substrate side, of the detection harness 52 isconnected to the connectors 48, 49 of the C/C 80. Specifically, as shownin FIG. 2, the detection harness 52 is led out for each of the cell packblocks 40, and as described above, since two cell pack blocks 40 areaccommodated in a battery module 9, two connectors 48, 49 are mounted onthe C/C 80. By arranging connectors respectively for the two cell packblocks, the wiring operation becomes simple. Also, maintenance can beperformed easily. One of the connectors 48, 49 is used for connection toa high voltage side cell in the cells connected in series, and the otherone of the connectors 48, 49 is used for connection to a low voltageside cell in the cells connected in series. Thus, the connection of thecells connected in series and the C/C 80 is divided into a plurality ofconnections based on potentials of the cells connected in series, andconnections of the cells and the C/C 80 are made using a plurality ofconnectors corresponding to the aforementioned division according topotential states. Accordingly, potential differences in connections bythe respective connectors can be made small. With such a structure,excellent effects can be obtained regarding withstanding voltage,leakage of current, as well as dielectric breakdown. Also, in connectingor releasing operation of each connector, it is difficult to connect orrelease the entire connector simultaneously, and a partial connectionstate is generated in the process of connecting or releasing. In theabove structure, the voltage difference held by each connector can bemade small, and thus electrical adverse effect due to a partialconnection generated in the process of connecting or releasing can besuppressed.

Also, on the substrate of the C/C 80, a plurality of ICs are preparedfor the serial connection of cells accommodated in the battery module 9.The number of cells handled by one IC is determined depending on theprocessing ability of each IC. In this embodiment, as will be describedlater with reference to FIG. 10, one IC is used for four cells. However,one IC may be used for five or six cells. Also, in the same system, apart in which one IC is used for four cells and a part in which one ICis used for six cells may be combined. The number of cells connected inseries is not limited to a multiple of an optimum number which can behandled by each IC. That is a multiple of four in this embodiment, butsince it is normally not limited to the multiple of four, a situationsuch that the number of cells handled by one IC is different within thesame system occurs. However, it would not be a big problem.

The cells connected in series are divided into a plurality of groupsbased on the number of cells handled by one IC, a corresponding IC isdetermined for every group, and the corresponding IC measures terminalvoltages of the cells constituting a corresponding group. As describedabove, numbers of cells constituting the respective groups may bedifferent.

In this embodiment, the number of cells which the cell pack 19 has andthe number of cells handled by one IC correspond by coincidence, andterminal voltages of the cells are measured by 12 ICs corresponding to12 cell packs 19. For increasing the reliability further, doubledsystems of circuit arrangements are formed, and hence 24 ICs IC-1A toIC-12B are mounted corresponding to 12 cell packs 19 as will beexplained below. These ICs are mounted in order corresponding to thecell packs 19, but details thereof will be described later with acircuit diagram.

Also, a communication harness 50 for communicating with a batterycontroller 20 (refer to FIG. 17) is led out from the substrate of theC/C 80, and the communication harness 50 has a connector on a tipportion thereof. This connector is connected to a connector (not shown)on the battery controller 20 side. Note that although chip elements suchas resistors, capacitors, photo couplers, transistors, diodes, and so onare mounted on the substrate of the C/C 80, these elements are omittedin FIG. 9 for avoiding complexity. On the substrate of the C/C 80, theconnectors 48, 49 are provided respectively for the two cell packblocks, and the communication harness 50 for communicating with thebattery controller 20 is provided separately from these connectors. Byproviding the connectors 48, 49 and the communication harness 50separately in this manner, the wiring operation becomes simple, and alsomaintenance becomes simple. Also, as described above, since one of theconnectors 48, 49 connects the cells connected in series on the highvoltage side and the substrate of the C/C 80, and the other one of theconnectors 48, 49 connects the cells on the low voltage side connectedin series and the substrate of the C/C 80, the voltage difference in arange held by each connector can be made small. When connecting orreleasing the connectors, a partial connecting state in which only apart thereof is connected is generated momentarily, but since thevoltage difference in the range held by each connector can be madesmall, an adverse effect brought about by the partial connecting statecan be made small.

The cell pack blocks 40 arranged and fixed in parallel on the lowercover 45 are connected with each other in series by block connecting busbars, which are omitted in the drawing. Grommets are fixed to thecircular holes formed in the front face portion of the lower cover base61, through which a positive electrode high voltage cable 81 and anegative electrode high voltage cable 82 are led out respectively (referto FIG. 2). In this manner, the battery module 9 has 12 cell packs 19connected in series and constitutes a battery with a nominal voltage of170 V and a capacity of 5.5 Ah. However, the lithium secondary cellschange in terminal voltage according to charge states, and actualterminal voltages will change based on the charge states.

Note that in respective groups in which cells connected in series aregrouped based on corresponding ICs, from one having a high potential toone having a low potential, a group on the highest potential side isrepresented by group AB1, a group having a next highest potential isrepresented by group AB2, . . . , and a group on a lowest potential sideis represented by group AB12. Also, a cell 10 having a highest potentialin cells constituting the group AB1 on the highest potential side isrepresented by cell B1, a cell 10 having a next highest potential in thegroup AB1 is represented by cell B2, . . . , a cell 10 having a lowestpotential on the group AB12 on the lowest potential side is representedby cell B48, and a cell 10 having a next lowest potential in the groupAB12 is represented by a cell B47. These cells will be explained withsymbols being added in order from the highest potential side to thelowest potential side (refer to FIG. 10).

Also, in this embodiment, the cell packs 19 and the groups correspond.This is because measurement of terminal voltages of four cells andbalance adjustment of charge states are performed by one IC. By managingfour cells by one IC, the number of cell packs and the number of groupscorrespond, but they need not necessarily correspond. A different numberof cells, six cells for example, may be managed by one IC. In the caseof six cells, the battery packs and the groups do not correspond.

Also, in this embodiment, the aforementioned temperature sensors arearranged in four cell packs 19 corresponding to the groups AB1, AB2,AB1, AB12, and for example provided respectively on a cell 1 (B1, B5,B41, B45) on the highest potential side in each of the cell packs 19corresponding to these groups.

As shown in FIG. 2, the upper cover 46 constitutes a left side face, anupper face, and a right side face of the module case 9 a. The uppercover 46 has a characteristic shape, and has upper cover narrow portions84 formed by narrowing front face and back face sides. Specifically,both ends of the left side face, the upper face, and the right side faceof the upper cover 46 are bent and narrowed toward the front face sideand the back face side of the lower cover base 61 respectively, so as toincrease durability in a torsional direction of the entire module case 9a. Also, on left and right side faces of the upper cover 46, collarguides 85 restricting movement of collars 91 (refer to FIG. 16) whichwill be described later are welded. From left and right sides of theupper cover 46, upper cover flange portions 86 each having asubstantially horizontal face extend outward. On the upper cover flangeportions 86, flange portion recesses 87 are formed so as to avoid theblock flanges A43 in a state that the block flanges A43 projecting fromthe block bases 41 are placed on the lower cover flange portions 68.

The lower cover flange portions 68 and the upper cover flange portions86 are fastened by screws and stud bolts. Also, the front face portionsand the back face portions of the upper cover narrow portions 84 and thelower cover base 61 are fastened by screws. Note that the upper covernarrow portions 84 form steps from the upper face of the upper cover 46,and thus screw heads after being fastened do not projects from the upperface of the upper cover 46 (also refer to FIG. 1). Further, femalescrews are formed on top portions of the center poles 66 provided tostand up on the lower cover base 61, and the upper cover 46 and thelower cover 45 are fastened by screws also at these positions. Asdescribed above, the module case 9 a has a structure with highmechanical strength against a force in a torsional direction. Also, thestructure can be easily assembled and is excellent in productivity.

<Cooling System of the Battery Module>

As shown in FIG. 6, the battery module 9 adopts a forcible coolingmethod to cool the respective cells 10 forcibly with cooling air by ablower fan 17 (refer to FIG. 17). Specifically, the cooling system ofthe battery module 9 has a structure such that cooling air introducedfrom the intake 14 passes through the inside of the introducing sidefixing table 62 of the lower cover 45, flows through the ducts 75 formedby the reinforcing louver 65 and the lower cover base 61 andcorresponding to the respective cell pack blocks 40, passes through therespective ventilation holes 76 formed in (the duct forming portions of)the reinforcing louver 65, flows around the respective cells 10constituting the respective cell packs 19 and converges in the spaceformed with the upper cover 46, passes from the discharge ports 72formed in the upper face of the discharging side fixing table 63 througha lower side of the C/C box 79 to exit via the exhaust port 15. Withsuch a structure, the battery module 9 has a structure which is compactand further has an excellent cooling effect.

The above-described arch-shape louver 36 and cross-shape louver 37 havea function as a support post between the two holders 11 constituting thecell pack 19, and a function as an inner louver. Here, important pointsfor cooling are positions of the ventilation holes 76 formed in thereinforcing louver 65 and opening areas thereof. In this embodiment, theblocking louvers 77 are provided in the ventilation holes 76 which arelocated on the introducing side, for example which are closest to theintroducing side, in intermediate portions the opening areas of theventilation holes 76 are made smaller with distance from the introducingside, and areas of the ventilation holes 76 which are located on theexhaust side, for example which are closest to the discharging side aremade large. With this structure, an excellent cooling effect can beobtained.

Since the cooling air which exchanged heat by forcible cooling convergeson the discharging side, sending a large amount of cooling air having alow temperature has a large effect in addition to the method ofincreasing flow speed by narrowing the opening areas of the ventilationholes 76. For example, an optimum cooling system can be constructed bysetting a ratio of the opening areas of the ventilation holes 76 to 0.7,0.25, 0.4, 0.7, 0.8, 1.0, 1.0, 1.0, 1.0, 1.0, 0.65 from the exhaustside, assuming that the center one is 1.0.

<Cell Controller>

As described above, the C/C 80 has a plurality of ICs, for example 24ICs IC-1A to IC-12B in this embodiment. These ICs are providedcorresponding to the groups AB1 to AB12 respectively. Specifically,IC-1A, IC-1B correspond to the group AB1 on the highest potential side,IC-2A, IC-2B correspond to the group AB2 having a next highestpotential, and IC-12A, IC-12B correspond to the group AB12 on the lowestpotential side. In this embodiment, mainly for ensuring reliability ofovercharging detection of the cells 10 (lithium secondary cells), thereare used two identical ICs, IC-1A and IC-1B corresponding to the groupAB1, IC-2A and IC-2B corresponding to the group AB2, . . . , IC-12A andIC-12B corresponding to the group AB12, respectively. Using two ICs foreach group, a doubled system is made to increase reliability. Note thatthe IC-1A and the IC-1B, the IC-2A and IC-2B, . . . , IC-12A and IC-12Bmay each be made as one IC to constitute all the ICs by half, 12 ICs.

As shown in FIG. 10, the IC-1A, IC-2A, . . . , IC-12A with “A” beingadded to the end (hereinafter, they are referred to as A-group ICsgenerically) have a function to detect voltages of the cells B1 to B4,B5 to B8, . . . , B45 to B48 constituting the respective correspondinggroups AB1, AB2, . . . , AB12 and a function to on/off control internalswitch elements (refer to symbols SW1 to SW4 of FIG. 11) so thatcapacity adjusting resistors R1 for adjusting capacities of cells B1 toB48 separately are connected in parallel to the cells, which are targetsof capacity adjustment, for uniformizing the capacities of all the cellsB1 to B48. On the other hand, the IC-1B, IC-2B, . . . , IC-12B with “B”being added to the end (hereinafter, they are referred to as B-group ICsgenerically) have a function to detect overcharging (FF) of the cells B1to B4, B5 to B8, . . . , B45 to B48 constituting the respectivecorresponding groups AB1, AB2, . . . , AB12 of cells. However, thefunction to detect overcharging (FF) may also be given to the IC-LA,IC-2A, IC-12A with “A” being added to the end. In this manner, the ICswith “B” being added to the end are completely for backing up.

The ICs each have terminals Vcc, BR1, CV2, BR2, CV3, CV4, BR4, VDD,TCLK, LIN12, LIN1, GND (ground), LIN2, FF1, FFO, and are constituted ofidentical circuits. In other words, the A-group ICs and the B-group ICsare constituted of ICs having the same circuit structure.

Next, a connection structure related to the IC-1A will be explained.Between respective positive and negative electrodes of the cells B1 toB4 constituting the group AB1 on the highest potential side, capacitorsC1 (1 nF in this example) for eliminating noise on a high frequency sideare connected in parallel respectively. Between the Vcc terminal and theCV2 terminal, between the CV2 terminal and the CV3 terminal, between theCV3 terminal and the CV4 terminal, and between the CV4 terminal and theGND terminal, capacitors C2 (100 nF in this example) for suppressingnoise of a low frequency side relative to the capacitors C1 areinserted, respectively. Specifically, the capacitors Clare provided onthe cell side of an inductance L which will be described below and thecapacitors C2 are provided on a voltage detecting circuit side of theinductance L so as to eliminate the noise of the high frequency side onthe cell side of the inductance L and eliminate the noise of the lowfrequency side from the capacitors C1 on the voltage detecting circuitside of the inductance L. Capacities of the capacitor C1 are smallerthan capacities of the capacitor C2. With the above structure, influenceof noise generated by the inverter device which converts direct currentpower to alternate current power can be reduced.

The Vcc terminal is connected to the positive side of the cell B1 via aninductor L (22 μH in this example). Note that for the inductor L, forexample one having a few μH (2 μH for example) to about 100 μH can beused. The BR1 terminal is connected to the negative electrode (positiveelectrode of the cell B2; as is clear from FIG. 10, since the negativeelectrode of the cell on the upper side and the positive electrode ofthe cell on the lower side, which are connected in parallel, have thesame potentials, hereinafter only negative electrodes of cells on theupper side will be explained) of the cell B1 via a capacity adjustingresistor R1 (for example, 200Ω), and the CV2 terminal is connected tothe negative electrode of the cell B1 via a resistor R2 (100Ω in thisexample) constituting an RC filter with the capacitors C1, C2, and theBR2 terminal is connected to the negative electrode of the cell B1 viathe capacity adjusting resistor R1. Here, capacity adjustment means toadjust the charge/discharge states of the cells 10 connected in seriesso as to uniformize them. In this embodiment, the charge/dischargestates of the cells 10 are controlled to be the same. For example, itbecomes possible that a cell having a charge amount larger than othercells is discharged via the capacity adjusting resistor to be adjustedto have the same state of charge (SOC) as other cells. By keeping thecells 10 in the same state of charge, it is possible to prevent acertain cell to be overcharged even when the state of charge of eachcell becomes close to a full charge.

The CV3 terminal is connected directly to the negative electrode of thecell B2. The BR3 terminal is connected to the negative electrode of thecell B3 via a capacity adjusting resistor R1, the CV4 terminal isconnected to the negative electrode of the cell B3 via a resistor R2,and the BR4 terminal is connected to the negative electrode of the cellB3 via the capacity adjusting resistor R1. Note that resistance valuesand functions of the resistors R1, R2 are the same as those explainedabove. Hereinafter, resistance values of resistors as well as capacitiesand functions of capacitors which are designated by the same symbols arethe same as in the contents already explained about the same symbols,and explanations thereof are omitted.

Also, a schottky diode D3 is inserted between the CV3 terminal and theVcc terminal, and a schottky diode D4 is inserted between the GNDterminal and the CV3 terminal. Further, a capacitor C3 (1 μF in thisexample), a capacitor C4 (100 nF in this example) and a capacitor C5(100 pF in this example) having different capacities are connectedbetween the GND terminal and the Vcc terminal. These capacitors suppressnoise which affects the IC-1A in a wide range. Also, a Zener diode ZD1for suppressing noise entering the Vcc terminal is inserted between theGND terminal and the Vcc terminal

Note that the Vcc terminal of each IC is connected to the terminal witha voltage of the highest order in the corresponding group of cells.Also, the GND terminal of each IC is connected to the terminal with avoltage of the lowest order in the corresponding group of cells. Forexample, in the IC-1A, the Vcc terminal is connected to a positiveelectrode of the cell B1 of the group AB1, and the GND terminal isconnected to the negative electrode of the cell B4 of the group AB1. Byconnecting in this manner, operational power for the IC corresponding toeach of the groups is supplied by all the cells of each of the groups,which are divided in groups, and hence the power consumption of thecells can be uniformized, thereby providing an effect leading touniformization of the states of charge of the cells. Also, in thisembodiment, the number of cells constituting a group is the same number,four in this example. Thus, by making numbers of cells constituting therespective groups the same, the operational power of the respective ICsare born by the respective cells evenly, thereby providing an effectleading to uniformization of the states of charge of the cells.

In FIG. 10, the communication harness 50 is connected to thehigher-order battery controller 20. However, the battery controller 20takes the chassis potential of a vehicle as ground (GND) potential andoperates with a low voltage of 5 volts. On the other hand, each IC takesa lowest-order potential of cells constituting the corresponding groupas GND potential and receives a highest-order potential in thecorresponding group at the Vcc terminal to operate. Accordingly, thecommunication harness 50 connected to the battery controller 20 needs tobe electrically insulated from the ICs. For making electricalinsulation, insulation circuits are provided on the higher-order sideand the lower-order side. A higher-order side interface is H-INT, and alower-order side interface is L-INT. Parts shown by dotted line in thesehigher-order side interface H-INT and lower-order side interface L-INTare converted. into light for transmitting information, and therebyelectrical insulation is maintained.

A capacitor C6 (100 nF in this example) is inserted between the GNDterminal and the VDD terminal (reference voltage terminal). Thecapacitor C6 is a capacitor for stabilizing an operating voltage of alogic circuit or the like in the IC-1A. A basic structure of the IC isshown in FIG. 11. A reference power supply circuit 104 receives the Vccvoltage supplied from the cells, and generates a constant voltage usedfor generating a voltage for operating a circuit in the IC and/or areference voltage which becomes a reference for comparison. The voltagegenerated by this reference power supply circuit 104 is also used as anoperating voltage of an analog-digital converter. Accordingly, it isdesirable that the reference power supply circuit 104 generates a stableconstant voltage in which influence of noise is eliminated as much aspossible. For that purpose, it is necessary to connect a smoothingcapacitor. Since it is not a good idea to provide a function of thesmoothing capacitor in the IC circuit, the VDD terminal is provided andthe capacitor C6 is connected between the aforementioned VDD terminaland the aforementioned GND terminal. The capacitor C6 is provided on thesubstrate of the C/C 80 explained with FIG. 9, and is connected to theVDD terminal and the GND terminal by wirings provided on the substrateof the C/C 80. The capacitor C6 is provided between the VDD terminal andthe GND terminal as shown in FIG. 10, and a degree of influence of noiseto the VCC power supply voltage and a degree of influence of noise tothe power supply voltage generated by the reference power supply circuit104 are different. Since strict noise measures are required for thepower supply voltage generated by the reference power supply circuit104, the VDD terminal is provided separately from a noise measure of theVcc terminal so that more excellent noise measures can be performed.With this structure in which the VDD terminal is provided and thecapacitor C6 is provided, there are effects such that detection accuracyof voltages of cells improves and thereby control accuracy of states ofcharge of the cells improves significantly.

The TCLK terminal is connected to the GND terminal and a functionthereof is stopped. Note that the IC-1A takes a principle that does notneed a common clock for transmission to an external circuit, and is madeso that it does not need to receive a special external clock. Forexample, a method is adopted such that clocks are adjusted with eachother at the time of starting transmission or reception, and a signal tobe transmitted is transmitted or received thereafter. Thus, it is notnecessary to receive a special clock signal from the outside, and thusthe circuit becomes quite simple. Specifically, this embodiment has acircuit structure in which reference potentials of the ICs and thebattery controller 20 are different respectively, and the referencepotentials of the ICs are determined by respective lowest potentials ofthe cells which are divided into groups. Further, the terminal voltageof a lithium cell varies largely by a charge/discharge state, and thereference potentials (potentials of the GND terminals) of the ICs varyconstantly. Therefore, it is not easy to provide a common clock circuitand supply this common clock to the ICs. In this embodiment, there is aneffect that the entire system can be simplified since a common clock isnot used.

The LIN12 terminal, the LIN1 terminal, and the LIN2 terminal areterminals for transmitting/receiving signals. Signal transmissionbetween the battery controller 20 and the ICs is signal transmissionbetween circuits having different potentials. A signal is transmitted tothe IC-1A and the IC-1B on the higher potential side and the IC-12A andthe IC-12B on the lower potential side using photo couplers forelectrical insulation. On the other hand, between the IC-1A on thehigher potential side and the IC-12A on the lower potential side orbetween the IC-1B on the higher potential side and the IC-12B on thelower potential side, communication is performed by a method ofconnecting input terminals and output terminals of the ICs in a looprespectively. The reception terminal LIN1 is connected to a receptionterminal LIN2 of a respective adjacent IC via a resistor R3 (470Ω inthis example) for reducing influence of noise. By connecting thetransmission and reception terminals connected in a loop via resistors,noise transmitted via the loop of transmission/reception can beattenuated, and there is an effect for reducing the influence of noisegenerated by the inverter device.

Also, the LIN12 is a terminal for supplying a current to a load to whichit is desired to supply a large current, and is connected directly to acollector on a photo transistor side of a photo coupler PH1 in thehigher-order side interface H-INT for performing communication with thebattery controller 20 in an insulated state. A transistor Tr1 andresistors R4, R5 for allowing stable operation of the transistor Tr1 areconnected to a light-emitting diode side of the photo coupler PH1. Theother end side of the resistor R5 is connected to the battery controller20 via a LIN reception line (Rx) which constitutes the communicationharness 50.

Between the GND terminal and the LIN1 terminal, a Zener diode ZD2 forprotection against a surge voltage is inserted. The LIN2 terminal isconnected (via a resistor R3) to the LIN1 terminal of the IC-2A as anA-group IC on the lower-order side. Therefore, the A-group ICs areconnected in a loop (hereinafter, referred to as a daisy chain)respectively by the LIN12 terminal, the LIN1 terminal, and the LIN2terminal. Note that the FFI terminal and the FFO terminal of the IC-1Aare not used.

Next, a connection structure related to the IC-1B will be explained.When seen from the group AB1 side constituted of cells, the IC-1B of theB-group IC is connected in parallel to the IC-1A of the A-group IC, andthis will be explained in detail as follows. Capacitors C2 are insertedbetween the Vcc terminal and the CV2 terminal, between the CV2 terminaland the CV3 terminal, between the CV3 terminal and the CV4 terminal, andbetween the CV4 terminal and the GND terminal, respectively. The Vccterminal is connected to a positive electrode of the cell B1 via aninductor L. The CV2 terminal is connected to a negative electrode of thecell B1 via a resistor R2, the CV3 terminal is connected to the negativeelectrode of the cell B2, and the CV4 terminal is connected to anegative electrode of the cell B3 via a resistor R2. The GND terminal isconnected to the GND terminal of the IC-1A. The capacitor C4 and thecapacitor C5 are connected between the GND terminal and the Vccterminal, respectively. Also, the capacitor C6 is inserted between theGND terminal and the VDD terminal, and the TCLK terminal is connected tothe GND terminal.

As compared to the case of the IC-1A, the connection structure of theIC-1B lacks the capacitors C1, C3, the inductor L, the schottky diodeD3, D4, the Zener diode ZD1, but as described above, this is becausethey are not needed to be provided redundantly since the IC-1B isconnected in parallel to the IC-1A. Meanwhile, since the capacitor C2,the resistors R2 and the capacitors C4, C5 have a purpose of suppressingnoise on the low frequency side mainly, they are also provided in theIC-1B because there may be influence thereof even when being connectedin parallel if a distance from the IC-1B is too far.

The LIN1 terminal is connected to a collector on a photo transistor sideof a photo coupler PH2 of a higher-order side interface H-INT via aresistor R3. A transistor Tr2 and resistors R4, R5 for allowing stableoperation of the transistor Tr2 are connected to a light-emitting diodeside of the photo coupler PH2. The other side of the resistor R5 isconnected to the battery controller 20 via an FF reception line (FFON)which constitutes the communication harness 50 and is for starting theseries of B-group ICs. Between the GND terminal and the LIN1 terminal, aZener diode ZD2 is inserted. The LIN12 terminal is connected directly tothe LIN2 terminal, and the LIN2 terminal is connected (via a resistorR3) to the LIN1 terminal of the IC-2B as a B-group IC on the lower-orderside. A purpose thereof is to reduce noise flowing through thetransmission/reception loop as explained above.

The LIN1 is an input terminal for transmitting a signal (controlinformation), and the LIN2 is an output terminal for transmitting asignal (control information). The internal structure of the IC will bedescribed later using FIG. 11, but as shown in FIG. 11, the LIN12terminal is connected to the terminal Vcc via a resistor R. As shown inFIG. 10, from the LIN12 terminal of the IC-1A, a voltage is supplied tothe collector on the photo transistor side of the photo coupler PH1 ofthe higher-order side interface H-INT. Specifically, a voltage suppliedto the Vcc terminal in FIG. 11 supplies a voltage to the collector onthe photo transistor side of the photo coupler PH1 from the LIN12terminal via the resistor R. A voltage is applied to the collector onthe photo transistor side of the photo coupler PH1 via the LIN1 terminalfrom a LIN reception circuit 106 of FIG. 11, but a voltage from theLIN12 terminal is supplied further. The photo transistor of the photocoupler PH1 performs conduction and a blocking operation based on anoptical input signal made by a signal transmitted thereto. Accordingly,an in-coming signal is transmitted to the LIN1 terminal of the IC. Forexample, when the photo transistor of the photo coupler PH1 turns to ablocked state based on an in-coming signal, the voltage of the LIN12terminal is applied to the LIN1 terminal via the resistor R3. On theother hand, when the photo transistor of the photo coupler PH1 turns toa conduction state based on an in-coming signal, the collector potentialof the photo transistor becomes a low potential, which is substantiallythe potential of the terminal GND of the IC, and lowers the voltage ofthe LIN1 terminal. When the photo transistor is in a conduction state, acurrent supplied from the LIN12 terminal as a collector current and acurrent supplied from the LIN1 terminal flow through the phototransistor. The potential of the LIN1 terminal rises by a voltage thatcorrespond to a voltage drop of the resistor R3, but it does not becomean obstruction particularly in operation.

The photo coupler PH1 consumes large power since it operates atrelatively high speed, and has a structure in which a current can besupplied also from the LIN12 terminal of the IC-12A. Since opponents ofconnection consumes small power, the IC-1B to the IC-12B other than theIC-1A do not necessarily need the function of the LIN12 terminal, butwith this terminal, power consumption of the ICs are uniformized and thepower consumption of the cells are uniformized. In this embodiment,since transmission of information is performed via a loop that goesthrough all the ICs, there is an effect that power consumption necessaryfor transmission/reception via the transmission/reception loop isuniformized for each of the ICs. Also, as described above, the Vccterminal of each IC is connected to a positive terminal of the highestorder cell in each cell group and meanwhile the GND terminal of each ICis connected to a positive terminal of the lowest order cell in eachcell group so that consumed power of each IC is supplied from cells ofthe entire cell group corresponding to this IC. Thus, there is an effectthat consumed power used for transmission/reception is shared in adirection to be uniformized for all the cells.

The FFI terminal and the FFO terminal are terminals for performingcommunication in a daisy chain about overcharging between the batterycontroller 20 and the B-group ICs. The FFI terminal is connected to acollector on a photo transistor side of a photo coupler PH3 of thehigher-order side interface H-INT via a resistor R3. A transistor Tr3and resistors R4, R5 for allowing stable operation of the transistor Tr3are connected to a light-emitting diode side of the photo coupler PH3.The other side of the resistor R5 is connected to the battery controller20 via an FF input line (FFIN) which constitutes the communicationharness 50 and is for performing overcharging detection conduction testof the B-group IC. Between the GND terminal and the FFI terminal, aZener diode ZD2 is inserted. On the other hand, the FFO terminal isconnected (via a resistor R3) to the FFI terminal of the IC-2B as aB-group IC on a lower order side.

Connection structures of the IC-2A, IC-2B are principally the same asthose of the IC-1A, IC-1B. Differences in the connection structures are,in the IC-2A, that the Vcc terminal is coupled directly to the GNDterminal of the IC-1A as a higher-order side A-group IC and that theLIN1 terminal is connected via a resistor R3 to the LIN2 terminal of theIC-1A, and in the IC-2B, that the LIN1 terminal is connected via aresistor R3 to the LIN2 terminal of the IC-1B as a higher-order B-groupIC and that the FFI terminal is connected via a resistor R3 to the FFOterminal of the IC-1B. Such connection structures are the same also forthe IC-3A, IC-3B, . . . , IC-11A, IC-11B. Note that the LIN12 terminalof the highest-order IC-1A is pulled up by the Vcc terminal in the IC(refer to FIG. 11), and used as a pull-up resistor by connecting theLIN12 terminal of the IC-1A to the photo coupler PH1.

The IC-12A, IC-12B located at the lowest order are principally the sameas the above-described connection structures. Differences in theconnection structures are, in the IC-12A, that the LIN2 terminal isconnected to an anode on a light-emitting diode side of a photo couplerPH4 of the lower-order side interface L-INT for performing communicationwith the battery controller 20 in an insulated state, and in the IC-12Bthat the FFO terminal is connected to an anode on a light-emitting diodeside of a photo coupler PH5 of the lower-order side interface L-INT. Atransistor Tr4 and a resistor R6 for allowing stable operation of thetransistor Tr4 are connected to the photo transistor side of the photocoupler PH4. The other end side of the resistor R6 is connected to thebattery controller 20 via a LIN transmission line (TX) which constitutesthe communication harness 50. On the other hand, a transistor Tr5 and aresistor R6 are connected to the photo transistor side of the photocoupler PH5. The other end side of the resistor R6 is connected to thebattery controller 20 via an FF output line (FFOUT) which constitutesthe communication harness 50. Note that in a circuit similar to thisembodiment, generally the voltage applied to the LIN1 terminal is higherthan an operating voltage of the IC.

The photo transistor of the photo coupler PH1 of the higher-order sideinterface H-INT is a circuit capable of transmitting/receiving a signalat high speed and consumes larger power than the other photo couplersPH2 and PH3. Also, it consumes larger power than other ICs, andaccordingly the power can be supplied thereto also from the LIN terminal12 in addition to the LIN1 terminal. In circuits of the IC-LB to IC-12B,opponents of transmission of the LIN2 terminal consume small power andhence do not necessarily need the LIN12 terminal. However, since it isbetter to uniformize power consumption of each cell as much as possible,the power consumption of the ICs is uniformized by connecting the LIN12terminal to the LIN2 terminal, and thereby the power consumption of thecells connected in parallel is uniformized.

Also, to make the noise suppressing effects the same by inserting aninductor in the GND line of all the ICs, an inductor L′ (22 μH in thisexample) is inserted between the negative electrode of the cell B48 ofthe lowest order and the ground (GND). Note that leads of theaforementioned temperature sensors TH1 to TH4 are relayed by thesubstrate of the C/C 80 (refer to TH1 to TH4 of FIG. 10) and connectedto the battery controller 20 by the communication harness 50.

Next, capacity adjustment of cells by the A-group ICs will be explainedbriefly. For example, when capacity (voltage) adjustment of the cell B2is attempted, a switch element SW2 such as FET provided between the BR2terminal and the CV3 terminal in the IC-1A is turned on for apredetermined time while discharging (also refer to FIG. 11) so as toallow a current to flow across a drain terminal and a source terminal ofthe switch element SW2 via the capacity adjusting resistor R1. Thiscurrent is heat-consumed by the capacity adjusting resistor R1, and thusthe capacity adjustment of the cell B2 can be performed.

The basic structure of each IC is shown in FIG. 11. Also, a basicstructure of a voltage detecting circuit 101 is shown in FIG. 18. EachIC is constituted having a voltage detecting circuit 101 constitutedhaving a multiplexer for selecting a cell as a voltage detection targetin a group constituted of cells and an AD converter for converting ananalog voltage of a cell selected by the multiplexer into a digitalvoltage, a reference power supply circuit 104 generating a referencepower supply with high precision, a logic circuit 103 having a logicaloperation function, a LIN reception circuit 106 with an input sideconnected to the LIN1 terminal and an output side connected to the logiccircuit 103, a LIN transmission circuit 107 with an input side connectedto the logic circuit 103 and an output side connected to the LIN2terminal, an FF input circuit 108 with an input side connected to theFFI terminal and an output side connected to the logic circuit 103, anFF output circuit 109 with an input side connected to the logic circuit103 and an output side connected to the FFO terminal, a switch controlcircuit 102 which is connected to the logic circuit 103 and controlsconduction and a blocking operation of switch elements SW1 to SW4 sothat they are connected in parallel to cells to which the capacityadjusting resistor R1 correspond, and so on.

The logic circuit 103 performs control of receiving information from thehigher order side and transmitting information to the lower order sideand further control of detecting terminal voltages of the cellsconstituting the corresponding group periodically by the voltagedetecting circuit, retaining values thereof, and transmitting thedetected terminal voltages of the cells based on an instruction of areceived signal.

As shown in FIG. 11, each IC has switch elements which are the same innumber as the cells constituting the corresponding group. In thisembodiment, each IC has four switch elements SW1 to SW4. The switchelement SW1 is connected in parallel between terminals of the cell B1via a resistor R1 shown in FIG. 10. Also, the switch element SW2 isconnected in parallel between terminals of the cell B2 via a resistor R1shown in FIG. 10. Similarly, the switch element SW3 is connected inparallel between terminals of the cell B3 via a resistor R1, and theswitch element SW4 is connected in parallel between terminals of thecell B4 via a resistor R1. With this circuit structure, a cell having alarger charge amount than a mean charge amount (mean capacity) of thecells can be uniformized in charge amounts by discharging charged powerby the aforementioned parallel circuit. Conduction and a blockingoperation of a discharge circuit by the aforementioned switch elementsare controlled by the switch control circuit 102. Since the switchelements SW1 to SW4 for uniformizing states of charge of cells are thusincorporated in each IC, the entire system can be simplifiedsignificantly, and workability in manufacturing steps of the batterymodule improves. Also, there is an effect that reliability of thebattery module also improves. Further, since the resistors R1 forconsuming power (refer to FIG. 10) is provided outside the IC, heatingof the IC can be reduced and enlargement of the IC can be reduced.

As shown in FIG. 18, the logic controller 103 controls a multiplexer MUXand an analog-digital converting circuit ADC periodically and detectsterminal voltages of the cells in the group corresponding to the IC in apredetermined order. When the multiplexer MUX selects the Vcc terminaland the CV2 terminal, the terminal voltage of the highest order cellamong the cells constituting the group is inputted to an operationalamplifier OPAMP. The terminal voltage inputted to the operationalamplifier OPAMP is reduced by a predetermined ratio and matched inreference potential, and converted into a digital value by theanalog-digital converting circuit ADC. The digitally converted terminalvoltage is stored temporarily in a circuit (refer to a shift register)of FIG. 11 and transmitted based on a transmission instruction.

In FIG. 18, when the multiplexer MUX selects the CV3 terminal, theterminal voltage of the second highest-order cell among the cellsconstituting the group is inputted to the operational amplifier OPAMP.Thus, by the multiplexer MUX, terminal voltages of the cells in thegroup are inputted to the operational amplifier OPAMP in order andreduced by a predetermined ratio and matched in reference potential, andconverted into a digital value. This control is repeated thereafter, andterminal voltages of the cells in the group corresponding to the IC aredetected in a predetermined order. In FIG. 18, the multiplexer MUX andthe operational amplifier OPAMP and the analog-digital convertingcircuit ADC operate with the potential of the terminal GND being thereference. The potential of the terminal GND changes by potentials ofthe cells, but since the multiplexer MUX and the operational amplifierOPAMP and the analog-digital converting circuit ADC change by the samereference potential, these circuits operate precisely. Since the largestvoltage Vcc in the corresponding group is inputted to the multiplexerMUX and the operational amplifier OPAMP, they are circuits capable ofcorresponding to a voltage higher than Vcc, for example up to 38 V. Onthe other hand, the analog-digital converter ADC is made to operate by aconstant voltage 3.3 V generated by the reference power supply circuit104 described in FIG. 11. Thus, terminal voltages of the cells can bemeasured accurately. In FIG. 18, an inputted potential of a terminalvoltage of each cell is converted in the operational amplifier OPAMP,and a change width of a terminal voltage of each cell as a target ofmeasurement is matched to a common range, withstanding voltage of acircuit of the analog-digital converting circuit ADC can be reduced.Also, as described above, there is an effect that the accuracy of theanalog-digital converting operation can be increased.

In FIG. 11, in each IC, a protection circuit constituted of diodes andZener diodes for protecting each IC from noise and surge voltage isprovided. These protection circuits include a diode D5 with an anodeside connected to the CV3 terminal and a cathode side connected to theVcc terminal, a Zener diode ZD6 with an anode side connected to the GNDterminal and a cathode side connected to the LIN1 terminal, a diode D7with an anode side connected to the GND terminal and a cathode sideconnected to the LIN2 terminal, a Zener diode ZD8 with an anode sideconnected to the GND terminal and a cathode side connected to the FFIterminal, and a diode D9 with an anode side connected to the GNDterminal and a cathode side connected to the FFO terminal.

<Noise Measures of the C/C 80 >

Here, noise and surge measures of the C/C 80 of this embodiment will beexplained. The following table 1 shows conditions of measures againstnoise generated by an opponent of connection of the battery module suchas an inverter.

TABLE 1 No. Contents Purpose 1 Inserting L To suppress LIN1 input noise2 Adding ZD1 between Vcc and To suppress Vcc noise GND 3 Adding ZD2between LIN1 and Surge protection GND 4 Inserting R3 in LIN1, FFI Toimprove noise resistance (input side) (output side protection) 5 AddingD3 between CV3 and Vcc Surge protection 6 Adding D4 between CV3 and Tosuppress dispersion in dark GND current, surge protection 7 Adding C3between Vcc and GND To suppress Vcc noise 8 Adding C2 between voltage Tosuppress low frequency detecting terminals side noise 9 Increasing areaof a ground To realize low impedance plane

1. Inserting an Inductor L

For example, focusing attention on A-group ICs, to suppress noise, asshown in FIG. 12(A), the Vcc terminal of a lower-order IC (for example,IC-7A) is connected via an inductor to a highest-order terminal of cellsconstituting a group, namely the GND terminal of a higher-order IC (forexample, IC-6A). As shown in FIG. 12(B), noise of 60 Vpp (peak-to-peakvolt) is applied to a group of cells corresponding to the lower-orderIC. By inserting the inductor between the Vcc terminal of the IC and theterminals of the cells, the noise is not superposed on the LIN2 terminalas shown in FIG. 12(D) despite the application of the noise. In otherwords, there is an effect of suppressing noise. However, as shown inFIG. 12(C), the noise is superposed on the LIN1 terminal, and it isdesirable that further improvement is made regarding suppression ofnoise in this part.

As shown in FIG. 13(A), in the C/C 80 of this embodiment, the Vccterminal of a lower-order IC (for example, IC-7A) is connected directlyto the GND terminal of a higher-order IC (for example, IC-6A).Therefore, with respect to the connection structure of FIG. 12(A), theinserting position of the inductor L is changed. As shown in FIG. 13(B),even when applying noise of 60 Vpp to a group constituted of cellscorresponding to the lower-order IC, the noise is barely superposed onthe LIN1 terminal as shown in FIG. 13(C). Also, the noise is notsuperposed on the LIN2 terminal (refer to FIG. 13(D)). Therefore, a moreexcellent noise suppressing effect than in FIGS. 12(A) to 12(D) can beobtained.

When 48 cells are connected in series, there may be noise due to avoltage variation in the battery unit or noise may be superposed on thebattery unit from the outside. It is conceivable that inserting aninductor as a noise measure is most effective. Also in the connectionstructure of FIG. 12(A), reliability against noise or surge can beincreased. In this embodiment, the structure of FIG. 13(A) is adoptedand an inductor L′ is further inserted between a negative electrode ofthe cell B48 and the ground (GND) so as to make noise suppressingeffects of all the ICs the same, and thus noise resistance of the C/C 80is improved. Also, in the above description the A-group ICs areexplained, but the same applies to the B-group ICs connected in parallelthereto.

2. Adding a Zener Diode ZD1 Between the Vcc Terminal and the GNDTerminal

As shown in FIG. 13(A), a Zener diode ZD1 for protecting the Vccterminal from noise is inserted between the Vcc terminal and the GNDterminal. Thus, the C/C 80 is further improved in noise resistance.

3. Adding a Zener Diode ZD2 Between the LIN1 Terminal and the GNDTerminal

As shown in FIG. 13(A), between the LIN1 terminal and the GND terminal,a Zener diode ZD2 for protecting the LIN1 terminal from a surge voltageis inserted. Thus, the C/C 80 of this embodiment is further improved insurge resistance.

4. Inserting a Resistor R3 in the LIN1 Terminal (Inserting a Resistor R3in the FFI Terminal)

As shown in FIG. 11, to protect the LIN terminal from a surge voltagewhen the battery is connected or operated, in the IC the diode D7 isinserted between the LIN2 terminal and the GND terminal, and the Zenerdiode ZD6 is inserted between the LIN1 terminal and the GND terminal.Also, between the Vcc terminal and the LIN2 terminal, a resistor R ofapproximately 5 kΩ is inserted. However, as shown in FIG. 14, when alarge surge voltage VN1 enters, the LIN1 terminal is restricted involtage by the Zener diode ZD6 and becomes a negative voltage. On theother hand, when the LIN1 terminal changes to have a negative voltage,current restriction is not applied in the LIN2 terminal of ahigher-order IC coupled directly to the LIN1 terminal, and hence it ispossible that a large current flows to the diode D7 and leads todestruction, which is preferred to be suppressed.

In the C/C 80, to prevent IC destruction, as shown in FIG. 13(A), theresistor R3 is inserted in the LIN1 terminal of the lower-order IC. Itis preferable that a resistance value of the resistor R3 is taken largein a range that it does not affect communication, and is set to 470Ωthat is a tolerated range of the IC maker. Note that although theA-group ICs are explained above, a diode D9 is inserted between the FFOterminal and the GND terminal and a Zener diode ZD8 is inserted betweenthe FFI terminal and the GND terminal as shown in FIG. 11, and there isa fear that a similar problem occurs also in the B-group ICs, which ispreferred to be suppressed. Therefore, a resistor R3 is inserted also inthe FFI terminal of a lower-order IC.

5. Adding a Schottky Diode D3 Between the CV3 Terminal and the VccTerminal

As shown in FIG. 10, a resistor R2 constituting an RC filter is insertedin the CV2 terminal and the CV4 terminal, but the CV3 terminal iscoupled directly to the negative electrode of the cell B2. As shown inFIG. 15, when the CV3 terminal of a higher-order IC (for example, IC-1A)and the GND terminal of a lower-order IC (for example, IC-7A) come incontact first at the time of connecting the battery, a high voltage isapplied between the CV3 terminal and the Vcc. terminal of thehigher-order IC, which can destroy the diode D5 inserted between the CV3terminal and the Vcc terminal in the IC. In this embodiment, to preventthis, the schottky diode D3 (with a rated current 1A in this example)having a small voltage drop is inserted between the CV3 terminal and theVcc terminal.

6. Adding a Schottky Diode D4 Between the CV3 Terminal and the GNDTerminal

As shown in FIG. 10, a schottky diode D4 (with a rated current 1A inthis example) is inserted between the CV3 terminal and the GND terminal.In reverse to the above item 5, when the Vcc terminal of a higher-orderIC and the CV3 terminal of a lower-order IC come in contact first, ahigh voltage is applied to a diode D10 (refer to FIG. 11), which candestroy the diode D10. To prevent this and also to suppress dispersionin dark current, a schottky diode D4 is inserted. The present inventorsinserted switches in all the voltage detecting lines 58 in the C/Ccircuit shown in FIG. 10 and conducted a connection test of the cellsand the C/C controller by turning on the switches from the higher-orderside, from the lower-order side, and in an arbitrary order, andconfirmed that the ICs (diodes D5, D10 therein) are not destroyed in anycase. Specifically, generation of surge cannot be avoided at the time ofconnecting the battery, but the present inventors confirmed that, byproviding the schottky diodes D3, D4 outside the ICs, most of thecurrent flows to the schottky diodes D3, D4 side and a current that isonly 1/20 of or lower than the current flowing through the schottkydiodes D3, D4 flows through the diode D5 in the ICs.

7. Adding a Capacitor C3 Between the Vcc Terminal and the GND Terminal

In the C/C 80, the capacitor C3 with a large capacity (1 μF in thisexample) is inserted between the Vcc terminal and the GND terminal.Accordingly, noise on the low frequency side entering the Vcc terminalcan be suppressed further.

8. Adding Capacitors C2 Between the Voltage Detecting Terminals

Also, in the C/C 80, besides the capacitors C1 which are connected inparallel to the respective cells and suppress noise on the highfrequency side, capacitors C2 having a larger capacity than thecapacitors C1 are inserted between the Vcc terminal and the CV2terminal, between the CV2 terminal and the CV3 terminal, between the CV3terminal and the CV4 terminal, and between the CV4 terminal and the GNDterminal, respectively. Accordingly, noise on the low frequency side(kHz order) can be suppressed for each IC when operating.

9. Increasing the Area of a Ground Plane

As shown in FIG. 10 and FIG. 13(A), in the C/C 80, the GND terminal of ahigher-order IC and the Vcc terminal of a lower-order IC can be coupleddirectly. Accordingly, in a C/C mounting substrate, every two circuitblocks (for example, IC-1A and IC-1B, IC-2A and IC-2B) can be coupleddirectly to form a large ground plane (so-called solid pattern) (referto chain lines in FIG. 9). Conventionally, the ground plane could beformed only in unit of one circuit block (for example, IC-1A and IC-1B).Accordingly, in the C/C 80, by enlarging the area of the ground plane,impedance can be lowered and noise resistance can be improved.

<C/C Mounting Substrate>

As shown in FIG. 10, the C/C 80 has a constraint that it is constitutedof, besides the 24 ICs, a large number of chip elements attachedexternally to these ICs, and a constraint that the signal outputterminals (LIN2 terminal, FFO terminal) and the signal input terminals(LIN1 terminal, FFI terminal) of the respective ICs are connected in adaisy chain. In view of these constraints, on the substrate of the C/C80, as shown in FIG. 9, the 24 ICs IC-1A to IC-12B are positioned andmounted corresponding to connection states of cells as measurementtargets. Potentials of cells connected in series vary according tocharged/discharged states of the battery, and potentials of cells asmeasurement targets of the respective ICs change. Accordingly, referencepotentials of the ICs change automatically. It is needed to performsending/receiving of a signal accurately between these changing ICs.Therefore, it is desirable to arrange ICs each including a measurementcircuit in a positional relationship related to the relationship of theserial connection of the cells as measurement targets. In this manner,complexity in signal transmission between ICs having differentpotentials is eliminated. Also, the signal transmission becomes simple,and reliability of sending/receiving signals becomes high. The signaltransmission between ICs having different potentials can be influencedin various ways, and hence it is desirable to reduce the possibility ofbeing influenced by external noise or stray capacitance for example. Inthis embodiment, the aforementioned influences are reduced by arrangingthe ICs in a related manner to the connection relationship of the cells.Further, since the respective ICs are in a positional relationship suchthat ones having close reference potentials are arranged closely,wirings for signal transmission become short, and various adverseinfluences such as the above influences are reduced. Thus, highreliability can be obtained.

In this embodiment, specifically, the ICs are mounted four by four onrectangular longer sides of a rectangular continuous straight line 1-1′defined on the substrate in order from the IC-1A, IC-1B on the highestpotential side to the IC-12A, IC-12B on the lowest potential sidecontinuously according to an order of potentials of the groupsconstituted of the cells. Also, in this embodiment, for mounting the 24ICs in a most compact manner, distances (lengths) between rectangularshorter sides of the rectangular continuous straight line 1-1′ are setto be the same. The ICs are mounted such that ones having closereference potentials are arranged closely.

Also, since the capacity adjusting resistors R1 generate heat duringcapacity adjustment in the capacity adjusting circuits each constitutedof a capacity adjusting resistor R1 and switch elements SW1 to SW4(refer to FIG. 11) in the A-group ICs, the 48 capacity adjustingresistors R1 are mounted by dividing in two and grouped in regions(dashed-line regions in FIG. 9) in the vicinity of the connectors 48, 49separated from the rectangular continuous straight line 1-1′. On theother hands, the photo couplers PH1 to PH3, the transistors Tr1 to Tr3,the resistors R4, R5, and the photo couplers PH4, PH5, the transistorsTr4, Tr5, the resistors R6 constituting the higher-order side interfaceH-INT and the lower-order side interface L-INT respectively arearranged, by dividing into the higher-order side and the lower-orderside, close to the connector from which the communication harness 50 isled out in upper regions (chain double-dashed line regions in FIG. 9) ofthe substrate. Note that other chip elements are mounted in the vicinityof the corresponding ICs. With such an arrangement, both the reductionin size and the improvement of reliability are possible.

<<Power Supply System>>

<High Voltage Circuit of the Power Supply System>

FIG. 17 shows a basic structure of a driving system of a vehicle andalso shows a power supply system in the driving system. As shown in FIG.17, the positive electrode high voltage cable 81 of one (lower potentialside) of the vertically stacked battery modules 9 is connected to a fuseside of an SD (service disconnect) switch 6 for maintenance andinspection in which a switch and a fuse are connected in series, and thenegative electrode high voltage cable 82 of the other one (high voltageside) of the vertically stacked battery modules 9 is connected to aswitch side of the SD switch 6. In other words, the two battery modules9 are connected in series via the SD switch 6, and constitute a highvoltage battery (battery with a power supply system in which two batterymodules 9 are connected in series) having a nominal voltage of 340 V anda capacity of 5.5 Ah. Note that for the fuse of the SD switch 6, onehaving a rated current of approximately 125 A can be used for example.With such a structure, high safety can be maintained.

Also, three high voltage relays, which are a negative electrode sidemain relay RL_(N) inserted between the negative electrode of the highvoltage battery and an inverter device 120, a positive electrode sidemain relay RL_(P) inserted between the positive electrode of the highvoltage battery and the inverter device 120, and a precharge relayRL_(PRE) connected in parallel with the positive electrode side mainrelay RL_(P) via a resistor R_(PRE), and a current sensor S_(I) such asa hall element inserted between the positive electrode side main relayRL_(P) and the inverter device 120 are included in a junction box. Notethat an output line of the current sensor S_(I) is connected to thebattery controller 20. For the positive electrode side main relay RL_(P)and the negative electrode side main relay RL_(N), one having a ratedcurrent of approximately 80 A can be used for example, and for theprecharge relay RL_(PRE), one having a rated current of approximately 10A can be used for example. Also, for the resistor R_(PRE), one having arated current of approximately 60 W and a resistance value ofapproximately 50Ω can be used for example, and for the current sensorS_(I), one having a rated current of approximately ±200 A can be usedfor example.

Therefore, the above-described negative electrode high voltage cable 82of the one battery module 9 and the positive electrode high voltagecable 81 of the other battery module 9 (the negative electrode and thepositive electrode of the high voltage battery) are connected to theinverter device 120 which drives a motor 130 of the hybrid vehicle viathe high voltage relays and the output plugs. With such a structure,high safety can be maintained.

The inverter device 120 has a power module 126 constituting an inverterwhich converts direct current power supplied from the power supply ofthe high voltage battery of 340 V into three-phase alternate currentpower for driving the motor 130, an MCU 122, a driver circuit 124 fordriving the power module 126, a smoothing capacitor (an electrolyticcapacitor or a film capacitor may be used) 128 having a large capacityof approximately 2000 μF.

When driving the motor 130, the MCU 112 turns the negative electrodeside main relay RL_(N) from an off state to an on state according to aninstruction from the higher controller 110, and thereafter, the MCU 112turns the positive electrode side main relay RL_(P) from an off state toan on state, thereby receiving power from the high voltage battery ofthe power supply system 1. Note that the inverter device 120 makes themotor 130 operate as a generator via a regulator when the hybrid vehicleis braking, namely, performs regenerative braking control, andregenerates the power generated by the generator operation for the highvoltage battery so as to charge the high voltage battery. Also, when thestate of charge of the battery module 9 decreases lower than a referencestate, the inverter motor controller 120 operates the motor 130 as agenerator, and the three-phase alternate current generated in the motor130 is converted into a direct current by an inverter constituted of thepower module 126, supplied to the battery modules 9 as the high voltagebattery and charged therein.

As described above, the inverter is constituted of the power module 126,and the inverter performs power conversion between direct current powerand alternate current power. According to an instruction from the highercontroller 110, the driver circuit 124 is controlled and a switchingoperation of the power module 126 is controlled so as to generate arevolving magnetic field in an advancing direction with respect torotation of a rotor of the motor 130, when the motor 130 is operated asa motor. In this case, direct current power is supplied to the powermodule 126 from the battery module 9. On the other hand, the drivercircuit 124 is controlled and a switching operation of the power module126 is controlled so as to generate a revolving magnetic field in adelaying direction with respect to the rotation of the rotor of themotor 130. In this case, power is supplied to the power module 126 fromthe motor 130, and direct current power of the power module 126 issupplied to the battery module 9. As a result, the motor 130 operates asa generator.

The power module 126 of the inverter device 120 performs conduction anda blocking operation at high speed to perform power conversion betweendirect current power and alternate current power. At this time, sincefor example a large current is blocked at high speed, a large voltagevariation occurs by inductance which the direct current circuit has. Tosuppress this voltage variation, the smoothing capacitor 128 with alarge capacity is provided in the direct current circuit. Heatgeneration by the power module 126 is a big problem in the inverterdevice 120 for mounting on a vehicle, and to suppress this heatgeneration, the operation speed of conduction and blocking in the powermodule 126 needs to be increased. By increasing this operation speed,jumping up of a voltage by the aforementioned inductance increases, andlarger noise occurs. Therefore, the capacity of the smoothing capacitor128 tends to be larger.

In an operation start state of the inverter, the charge in the smoothingcapacitor is substantially zero, and a large initial current flows invia the relays. Since an initial flow-in current from the high voltagebattery to the smoothing capacitor 128 becomes large, the negativeelectrode side main relay RL_(N) and the positive electrode side mainrelay RL_(P) may fuse and get damaged. Accordingly, in the initialstate, after turning the negative electrode side main relay RL_(N) froman off state to an on state, the MCU 122 leaves the positive electrodeside main relay RL_(P) in an off state but turns the precharge relayRL_(PRE) from an off state to an on state to restrict the current viathe resistor R_(PRE), and meanwhile charges the above-describedsmoothing capacitor in this state. After this smoothing capacitor ischarged to a predetermined voltage, the initial state is released. Thenegative electrode side main relay RL_(N) and the positive electrodeside main relay RL_(P) are turned to on states, to thereby supply directcurrent power to the power module from the power supply system 1 asdescribed above, without using the precharge relay RL_(PRE) and theresistor R_(PRE). By performing such control, the relay circuits areprotected and safety of the inverter device 120 can be maintained.

Since reduction of the inductance on the direct current side circuit ofthe inverter device 120 leads to suppressing of noise voltage, thesmoothing capacitor 128 is arranged close to a direct current sideterminal of the power module 126. Also, the smoothing capacitor itselfis made to be capable of reducing the inductance. When the initialcharge current of the capacitor is supplied in such a structure, thereis a fear that high heat is generated to cause damage. This damage canbe reduced by the precharge relay RL_(PRE) and the resistor R_(PRE).Control of the inverter device 120 is performed by the MCU 122, but asdescribed above, control for initially charging the capacitor 128 isalso performed by the MCU 122.

As the smoothing capacitor, an electrolytic capacitor or a filmcapacitor is used. In a capacitor, performance decreases at a lowtemperature. Particularly, the function of the electrolytic capacitordecreases, and an elimination effect of noise thereof decreases. Noisethat cannot be eliminated by the capacitor 128 is applied to the powermodule, which may cause malfunctioning in the circuit of FIG. 10 as wellas damaging to the IC circuit. In the explanation above and theexplanation below regarding measures against noise, large effects areexhibited for measures against noise generated by the inverter device120.

To the connection line between the negative electrode of the highvoltage battery of the power supply system 1 and the negative electrodeside main relay RL_(N), and to the connection line between the positiveelectrode of the high voltage battery and the positive electrode sidemain relay RL_(P), capacitors C_(N), C_(P) are inserted between thenegative and positive electrodes and a case ground (the same potentialas the vehicle body of a vehicle) respectively. These capacitors are forremoving noise generated by the inverter device 120 to preventmalfunctioning in the low voltage circuit as well as destruction of theICs constituting the C/C 80 due to a surge voltage. The inverter device120 has a noise eliminating filter, but these capacitors are insertedfor further increasing the effect of preventing malfunctioning in thebattery controller 20 and the C/C 80 and for further increasingreliability of the power supply system 1 against noise. Note that inFIG. 17, the high voltage circuit of the power supply system 1 is shownby bold lines. For these lines, straight angle copper wires having alarge cross section are used.

<Low Voltage Circuit of the Power Supply System>

As elements to constitute the low voltage circuit, the power supplysystem 1 has the battery controller 20, the DC/DC converter included inthe converter box 21 and supplying 12 V power to the battery controller20, the blower fan 17, a relay 94 integrated with the blower fan 17 as aunit for operating the blower fan 17, the above-described C/C 80 and thecurrent sensor S_(I).

The DC/DC converter in the converter box 21 receives power from a 24 Vlead battery (not shown) as a power supply of a hybrid vehicle (enablesan auxiliary such as a lamp to operate), converts the 24 V voltage to 12V by a chopper circuit, a smoothing circuit or the like, and supplies aconstant voltage of 12 V as operational power supply for the batterycontroller 20. The DC/DC converter is connected to an on terminal of anignition switch IGN (refer to the IGN_ON (24 V) line in FIG. 17), startsto operate when the ignition switch IGN is located at an on position tosupply power to the battery controller 20 continuously, and stops thepower supply to the battery controller 20 when the stop of the powersupply is instructed by the battery controller 20 via a shutdown controlline. With such a structure, the power supply system with highreliability is realized.

The battery controller 20 has an MPU which performs various types ofprocessing operations as will be described later, a non-volatile EEPROM,an AD converter, a DA converter, a total voltage detecting circuit fordetecting the total voltage of the two battery modules 9 connected inseries (high voltage battery), and a 5 V power generation circuit whichgenerates 5 V power from 12 V power supplied via the DC/DC converter(refer to FIG. 10).

The total voltage detecting circuit is constituted of an HV+ terminalconnected to the positive electrode of the high voltage battery, analternate current converter connected to an HV-terminal which isconnected to the negative electrode of the high voltage battery forconverting the total voltage of the high voltage battery to an alternatecurrent, a transformer for insulating the high voltage of the highvoltage battery, a dividing resistor which divides the voltage on anoutput side of the transformer, a direct current converter whichconverts a voltage divided by the dividing resistor from an alternatecurrent voltage to a direct current voltage, a differential amplifierconstituted of an OP amplifier and a resistor for grasping the directcurrent voltage converted by the direct current converter, and an ADconverter which converts an analog voltage outputted from a differentialamplifier to a digital voltage, and an output terminal of the ADconverter is connected to the MPU. Therefore, the MPU can take in thetotal voltage of the high voltage battery by a digital value. With sucha structure, high precision can be maintained, and the high reliabilityis maintained.

The battery controller 20 is connected to the on terminal of theignition switch IGN, and communicates with the higher controller 110 viaa communication line 96 included in a main cable (refer to FIG. 17) ledout from the power supply system 1. Also, the output line from thecurrent sensor S_(I) is connected to the MPU via an AD converter, andthe MPU can take in the current flowing in the high voltage battery by adigital value. Further, in the battery controller 20, a DA converter anda transistor are arranged, and the MPU turns the relay 94 to an on statevia the DA converter and the transistor to operate the blower fan 17. Bysuch operations, highly reliable control is possible.

Also, the battery controller 20 is connected to the C/C 80 via thecommunication harness 50 and is capable of communicating therewith, butas described above, the communication harness 50 also includes outputlines from temperature sensors TH1 to TH4 (refer to FIG. 10). Theseoutput lines are converted into digital signals by an AD converterincluded in the battery controller 20, supplied to the MPU included inthe battery controller, and used for various controls.

(Assembly Procedure)

Next, an assembly procedure of the power supply system 1 of thisembodiment will be explained in phases in an order of the cell pack 19,the cell pack block 40, the battery module 9, and the power supplysystem 1.

<Assembly Procedure of the Cell Pack 19>

In FIG. 1 to FIG. 8, an adhesive is applied to curving portions of theholder 11 which contact the cells 10, the cells 10 are arranged so thatthe polarities thereof are alternated, and pressure is applied theretoto make snap-fitting between the two holders 11 and the cross-shapelouver 37 to be a support post between the holders 11 to function. Next,the metal bus bars insert molded in the holder 11 are spot-welded withthe respective cells 10. Note that although final fixing of the cells 10and the two holders 11 depends on the adhesive, there is adopted astructure in which the physical locking force by the snap-fitting holdsenough until the adhesive dries out and solidifies. Accordingly, it ispossible to proceed to respective steps of welding, inspecting, andassembling after the adhering step without waiting for passing of adrying time period, and thus the time efficiency increases.

Further, it is adopted a structure such that the voltage detecting lines58 (refer to FIG. 10) are gathered on a connector via the not-shownflexible substrate (one end side of the flexible substrate serves as theconnector), and the voltage detecting lines are gathered on theconnector just by welding the cells 10 to the metal bus bars. Theconnector is fixed in advance to one of the holders 11 (holder 11 on theright side in FIG. 7). Accordingly, connection of the voltage detectinglines 58 can be simplified significantly.

<Assembly Procedure of the Cell Pack Block 40>

The cell packs 19 produced as above are arranged in parallel as shown inFIG. 3 so that the two block bases 41 face each other, and fixed bytapping screws 42. As shown in FIG. 5, after the cell packs 19 are fixedon the block bases 41, the block reinforcing plates 51 are arranged onupper portions of the cell packs 19, and fixed by tapping screws 42similarly to the fixing of the block bases 41. At this time, on a facewhere the voltage detecting lines 58 are arranged, cable ties 55 forattaching the tie bands 54 are attached by tapping screws 42 at fourpositions. Thereafter, the detection harness 52 is arranged in thevicinity of the cable ties 55, and fixed by the tie bands 54 to the cellpack block 40. Then, six connectors provided on the other side (oppositeside of the harness connector) of the detection harness 52 are inserted(connected) to the connectors of the six cell packs 19 constituting thecell pack block 40 respectively, thereby completing assembly of the cellpack block 40. With such a structure and an assembly method, there is aneffect that workability improves.

<Assembly Procedure of the Battery Module 9>

As shown in FIG. 2, the cell pack blocks 40 are arranged on and fixed tothe lower cover 45. At this time, in the cell pack blocks 40, hooks madeof thick wire are inserted in the circular holes of the blockreinforcing plate curving portions 56 of the block reinforcing plates 51for performing handling such as carrying. In the circular holes 47formed in both ends of the block bases 41 of the cell pack blocks 40,the stud bolts 78 on the introducing side fixing table 62 and thedischarging side fixing table 63 constituting the lower cover 45 arepassed through and fastened and fixed by nuts including springs. Afterthe two cell pack blocks 40 are arranged in parallel and fixed, it isconfirmed that the block flanges B44 projecting from the block bases 41of the cell pack blocks 40 oppose each other on the block fixing bases64, and then the block flanges B44 are fastened by nuts includingsprings.

When fastening of the cell pack blocks 40 is finished, the C/C box 79including the C/C 80 is inserted between the cell pack blocks 40 on thedischarging side fixing table 63 of the lower cover 45 and the lowercover 45, and the connectors on the tips of the detection harnesses 52(two are led out as shown in FIG. 2) are engaged with the connectors 48,49 of the C/C 80 respectively. Thereafter, the C/C box 79 is slid towardand pushed against a side wall of the back face of the lower cover 45,and is fixed by screws from the outside of the battery module 9. Thereare four fixing points of the C/C box 79, and the C/C box 79 is fixed bylateral fixing from the back face of the lower cover 45 and upper sidefixing to welding nut portions provided on the discharging side fixingtable 63. To fasten the connectors with each other, the detectionharnesses 52 side needs allowances for stroke amounts to insert theconnectors, but having such allowances makes the harnesses longer thannecessary. The required allowances can be minimized by connecting theconnectors with each other at the stage that the C/C box 79 is not fixedand hence free, and then sliding the C/C box 79 to the fixing point.

The block connecting bus bars for electrical connection between the cellpack blocks 40 are fastened by attaching screws, and the positiveelectrode high voltage cable 81 and the negative electrode high voltagecable 82, which have grommets and are fixed to the lower cover 45 inadvance, are connected to the respective cell pack blocks 40 andfastened by screws. Since crimp terminals are connected to ends of thesehigh voltage cables, attaching of them can be performed easily.

After all the electrical connections are finished, the upper cover 46 isplaced and the lower cover 45 and the upper cover 46 are fastened byscrews. Specifically, the covers are fastened by screws with the studbolts 88 disposed to stand up on the lower cover flange portions 68 ofthe lower cover 45 via the circular holes formed in the upper coverflange portions 86 of the upper cover 46. At this time, the blockflanges A43 projecting from the block bases 41 are positioned on thelower cover flange portions 68, and fastens the upper cover 46 and thelower cover 45 in the flange portion recesses 87, and also fastens thecell pack blocks 40. Also, the upper cover narrow portions 84 arefastened with the lower cover 45 with screws, and by fastening the upperface of the upper cover 46 and the center poles 66 with screws, assemblyof the battery module 9 is completed.

<Assembly Procedure of the Power Supply System 1>

The power supply system 1 is accommodated in an external box constitutedof a lower container accommodating two battery modules 9 for example(refer to FIG. 16), and an upper cover which encloses an upper openingof this lower container. First, output plugs and cables are attached tothe lower container. At this time, the SD switch 6 is arranged andfixed. Note that as shown in FIG. 17, the cables are constituted of aninput line (24 V, GND) to the DC/DC converter, an IGN-ON (24 V) line,the communication line 96, and input lines to the negative electrodeside main relay RL_(N), the positive electrode side main relay RL_(P),and the precharge relay RL_(PRE).

Next, the battery modules 9 are inserted in the lower container to whichthe cables are fixed. At this time, the ventilation duct is attached tothe module case 9 a. The battery modules 9 may be inserted by hangingthem with a rope or the like, but the most efficient manner is to use asuction pad, which allows lifting with a suction cup. The first-levelbattery module 9 is fastened by screws and the second-level batterymodule 9 is fixed using the collars 91, the long bolts 92 (refer to FIG.16). Next, as shown in FIG. 17, a blower duct case in which the blowerfan 17 and the relay 94 are integrated, a relay case 18 including therelays, the converter box 21 including the DC/DC converter and thebattery controller 20 are arranged above the battery modules 9 and fixedthereto, and the blower fan 17 and the battery modules 9 are connectedby ducts which are prepared in advance so as to secure distributionpaths of cooling air. Next, the high voltage cables are connected to thebattery modules 9 and the output terminals of the battery modules 9 andthe SD switch 6 are connected so as to make electrical connectionsinside the power supply system 1. Then, the flanges of the upper coverand the lower container are stacked via a gasket and fixed with eachother by fastening with screws, thereby completing assembly of the powersupply system 1.

(Operation)

Next, with reference to FIG. 10, FIG. 11 and FIG. 17, the operation ofthe power supply system 1 of this embodiment will be explained with theICs of the C/C 80, the MPU of the battery controller 20 and the highercontroller 110 being main objects.

<Startup and the Like>

When the ignition switch IGN is positioned at an on position, the DC/DCconverter in the converter box 21 receives power from the 24 V leadbattery, converts the 24 V voltage into a 12 V voltage, and supplies 12V power to the battery controller 20. Accordingly, the MPU of thebattery controller 20 executes initial setting processing according to aprogram and program data which are expanded in a RAM, and when the MPUrecognizes that the ignition switch IGN is positioned at the onposition, the MPU starts the respective ICs IC-1A to IC-12B of the C/C80 which are in a sleep state. Specifically, the MPU outputs a startupsignal (wakeup signal) to the LIN reception line (Rx) and the FFreception line (FFON) and transmits a startup signal to the A-group ICIC-1A and the B-group IC IC-1B via the photo couplers PH1, PH2 of thehigher-order side interface H-INT.

As such a signal, for example, a five-byte signal can be used, in which8 bits are one unit. In this example, the signal is constituted of abreak field (first 8 bits) indicating an arrival of a signal, asynchronized field (second 8 bits) for synchronization, an identifierfield (third 8 bits) for identifying that it is a command (controlinstruction) to a particular IC, a data field (fourth 8 bits) expressingcommand contents, and a check digit (fifth 8 bits). With such a startupmethod, it is possible to suppress power consumption when an operationis stopped, and also there is an effect that a start operation of eachIC can be performed via the loop signal transmission path. Also,reliability of the operation is high.

The LIN reception circuit 106 of the IC-1A converts a potential of asignal transmitted to the LIN1 terminal and transmits this signal to thereference power supply circuit 104. Accordingly, the reference powersupply circuit 104 starts up, and the reference power supply circuit 104charges the capacitor C6 which is externally attached to the IC-1A via atransistor which is omitted in the drawings. When the voltage of thecapacitor C6 becomes a specified value or larger that is slightlysmaller than a voltage (5 V) added to the VDD terminal, the logiccircuit 103 starts up. Thereafter, the voltage of the capacitor C6 iscontrolled to be a constant value (5 V or 3.3 V or the like). The logiccircuit 103 recognizes the startup signal transmitted from the MPU andtransmits this by the LIN transmission circuit 107 via the LIN2 terminalto (the LIN1 terminal of) the following IC-2A on the lower potentialside. Similarly, thereafter the IC-2A to IC-12A start up. The IC-12Areturns the startup signal to the MPU via the photo coupler PH4 of thelower-order side interface L-INT. Such a startup operation is the samefor the B-group ICs, but the IC-12B returns the startup signal to theMPU via the photo coupler PH5 of the lower-order side interface L-INT.The capacitor C6 is provided for stabilizing the reference power supplycircuit 104, but also performs the operation as described above.

The MPU recognizes that all the ICs start up from the sleep state by thereturned signal. Next, the MPU outputs a test signal to the FF inputline (FFIN) and confirms whether it can be transmitted normally betweenthe groups when all the B-groups detect overcharging (FF). When the testsignal is inputted to the FFI terminal, the IC-1B in which the logiccircuit 103 is started up outputs the test signal as it is (the testsignal stored once in the register) via the FFO terminal from the FFoutput circuit 109 to (the FFI terminal of) the lower-order IC-2B.Thereafter, similarly, the test signal is transmitted to the IC-3B toIC-12B, and the IC-12B returns the test signal to the MPU via the photocoupler PH5 of the lower-order side interface L-INT. Thus, the MPU canrecognize that there is no functional disorder in the B-group ICs orthere is no breaking or the like in the transmission system (network)connected in a daisy chain.

After started up, the B-group ICs operate independently from the A-groupICs, and when any IC belonging to the B-group ICs detects overcharging(FF) of a cell, the FFI terminal and the FFO terminal up to the IC-12Buse the transmission system to notify the overcharging of a particularcell to the MPU via the photo coupler. PH5 from the FFO terminal of theIC-12B. By the above-described test during startup and the independentoperation of the B-group ICs, high safety and reliability can be ensuredeven when lithium secondary cells are used for the cells 10. Note thatthe B-group ICs determine in the logic circuit whether the voltage ofeach cell measured by the voltage detecting circuit surpasses apredetermined overcharge voltage (for example, 4.35 V), and determine asovercharging when it surpasses and as normal when it does not surpasses.In this case, in the signal transmitted between the B-group ICs and tothe MPU, the identifier field has information for identifying the ICwhich detected the overcharging, and the data field has information foridentifying the cell which is overcharged. With such a structure and adetecting method, reliability of the detection improves, and moreoversafety of the system improves.

When the MPU is notified of overcharging, it notifies this to the highercontroller 110. The higher controller 110 immediately stops charging ofthe high voltage battery by regenerative braking of the inverter device120 or charging of the battery by operation as a generator, and foreliminating the overcharging state of the particular cell, the highercontroller 110 allows the vehicle to run with the motor 130 in apowering operation mode, namely, an operation mode in which the drivingtorque of the vehicle is generated by the motor 130. This operation modeis achieved by that the position of a revolving magnetic field generatedat the rotor of the motor 130 by the operation of the inverter device ison an advancing side than the magnetic pole position of the rotor of themotor 130. In other words, when the revolving magnetic field generatedby the rotor is allowed to revolve at the same speed as the rotationspeed of the rotor of the motor 130, the motor 130 turns to a state ofgenerating neither voltage nor torque. In this state, charging of thebattery stops. Further, when the revolving magnetic field generated bythe rotor is made faster than the rotation speed of the rotor of themotor 130, the motor 130 generates torque and consumes the power of thebattery. With such a method and a system structure, there is an effectthat high safety can be maintained.

When recognizing there is no problem in the B-group ICs, the MPU reportscompletion of starting up to the higher controller 110 via thecommunication line 96, and thereafter proceeds to the next instruction.Specifically, the MPU transmits a command to the IC-1A to IC-12A usingthe photo coupler PH1 of the higher-order side interface H-INT. Such acommand includes, as will be described later, a voltage detectioninstruction of each cell and/or a capacity adjustment instruction.

The IC-1A converts the potential of a command signal obtained at theLIN1 terminal in the LIN reception circuit 106, and decrypts the signalin the logic circuit 103. Then, the signal is stored once in a registerand the same signal is sent to the IC-2A via the LIN transmissioncircuit 107. The lower-order IC-2A to IC-12A executes similaroperations. Then, the lowest-order IC-12A returns the command signal tothe MPU via the photo coupler PH4.

The MPU confirms the returned command signal, and if it is normal, theMPU sends a next control instruction. The MPU integrates the number oferrors related to a signal voltage, and when the number is equal to orlower than a tolerable number, sends the same command signal to theIC-1A for doing the process over. On the other hand, when a ratio of thenumber of errors reaches a tolerable value or above, the MPU judges thisas abnormality and outputs an abnormality signal to the highercontroller 110.

The IC-1A to IC-12A of the C/C 80 are connected in a daisy chain by theLIN1 terminals and the LIN2 terminals, and since control information istransmitted via a command signal, there is a time delay until controlinformation reaches the IC-1A to the IC-12A. However, a voltagevariation in the cells 10 during this period is quite small, and henceno problem occurs in practice. On the other hand, even when an erroroccurs in any one of the ICs, the MPU can detect this by comparing thecommand signal transmitted to the IC-1A with the command signal returnedfrom the IC-12A. Particularly, in the power supply system 1 of thisembodiment sending a command signal via the interfaces H-INT, L-INT,including the DC/DC converter and being connected to the inverter device120, it is necessary to consider the influence of noise generated bythem. The MPU can confirm that every command is recognized precisely inall the IC-1A to IC-12B, and thus the reliability of the system can beimproved. Specifically, with the above-described starting method,control with high reliability becomes possible. Also, an abnormal statecan be confirmed, and hence control with high safety can be realized.

<Voltage Detection>

When the power supply system 1 is in a charge/discharge stop state, theMPU transmits a voltage detecting command to the IC-1A to IC-12A via thephoto coupler PH1. The MPU can determine whether the power supply system1 is in any one of a charged state, discharged state, and a halt stateby monitoring the output from the current sensor Si. When the vehicle isrunning, charging/discharging are performed between the high voltagebattery and the inverter device 120, and hence the voltage detectingcommand is executed when it is in the charge/discharge stop state of thebattery. Also, in the case of a lithium secondary cell in whichamorphous carbon is used as a negative electrode active material incells, correlation between an open circuit voltage of a cell and a stateof charge (SOC) or capacity thereof is quite high. By sending thevoltage detecting command while in the charge/discharge stop state, acell state such as SOC of each cell can be grasped accurately.

The MPU and the IC-1A to IC-12A execute the above-described operation atthe startup time, and the MPU reports that the startup is completed tothe higher controller 110 via the communication line 96. Upon receptionof this report, the higher controller 110 issues the voltage detectinginstruction to the MPU.

The MPU issues the voltage detecting command for a cell B1 to the IC-LA.The IC-1A stores command data in a register, and by sending the samecommand to the lower-order IC, the command is returned to the MPU. Thismethod is similar to the above-described method. The logic circuit 103of the IC-1A decrypts this voltage detecting command, and specifies thecell B1 as the voltage detecting target to the multiplexer MUX of thevoltage detecting circuit 101 and obtains a digital voltage value of thecell as the voltage detecting target via the analog-digital convertingcircuit ADC. Next, by transmitting the obtained digital voltage value ofthe cell B1 as the voltage detecting target to the lower order IC, theMPU obtains a digital voltage value of the cell B1. Thereafter, the MPUsequentially repeats the voltage detecting command for the cellsimilarly to obtain digital voltage values of the cells B1 to B48. Thus,detection of a voltage with high reliability can be performed, and theSOC of a cell can be grasped with high accuracy. Note that the A-groupICs may be configured to store a measured voltage of a cell in aregister and output the stored voltage in the register when it receivesa voltage output command, which is different from the voltage detectingcommand.

The MPU confirms whether the command returned from the IC-12A has anerror or not (if so, sends the same command again). Thereafter, the MPUtakes in temperature values of cells B1, B5, B41, B45 detected by thetemperature sensors TH1 to TH4 via the AD converter, and calculates anarithmetic mean value of the taken temperature values. Next, the MPUcalculates SOCs of the obtained respective cells B1 to B48.

<Normal Operation>

At every predetermined time, the MPU reports to the higher controller110 via the communication line 96 the SOC (state of charge) of all thecells B1 to B48 constituting the power supply system 1, a dischargeableoutput capacity, a chargeable output capacity, a mean temperature of thecells, the total voltage of the high voltage battery, a charge current,a discharge current, and so on.

Specifically, the MPU calculates the SOC of the cells B1 to B48 afterstartup, and begins integration of charge currents and dischargecurrents respectively, which are detected by the current sensor S_(I).Also, the MPU takes in the voltage of the high voltage battery from theabove-described total voltage circuit. Further, the MPU calculates thearithmetic mean value of the cell temperatures detected by thetemperature sensors TH1 to TH4. Then, using the taken voltage of thehigh voltage battery, the integrated value of charge currents, theintegrated value of discharge currents and the mean temperature of thecells, the MPU calculates the SOC of the cells B1 to B48, and alsocalculates a current dischargeable output capacity and chargeable outputcapacity. Note that the MPU turns the relay 94 to an on state to makethe blower fan 17 operate for cooling all the cells constituting thehigh voltage battery at the time of startup. Accordingly, thereliability of control improves, and also cooling with higherreliability becomes possible.

<Capacity Adjustment>

As described above, the MPU grasps the SOC of all the cells B1 to B48constituting the power supply system 1 at the time of startup. Whenthere is dispersion of a specified value or larger in SOC of all thecells B1 to B48, an adjusted capacity for a cell (the cell as a capacityadjustment target) that exceeds a specified value is calculated so thatthe range of dispersion is in the range of the specified value, and acapacity adjustment time corresponding to the calculated adjustmentcapacity is calculated. Since resistance values of the capacityadjusting resistors R1 are known, the capacity adjustment time can beeasily calculated with reference to a table for example. When the powersupply system 1 is in a charge/discharge state, the MPU sends a capacityadjustment command for the cell as a capacity adjustment target to theIC-1A to IC-12A via the photo coupler PH1. The data field of thiscommand includes information regarding the capacity adjustment time.

Such capacity adjustment is for preventing that a desired function asthe battery module or the entire high voltage battery is not exhibitedwhen there occurs dispersion in SOC of cells because a cell in whichdispersion occurred becomes a load on other cells, and also for that itis necessary to assure a desired lifetime as the battery module or theentire high voltage battery, as a cell in which dispersion occurredtends to have a lifetime shorter than a designed lifetime. Therefore, itis preferable to perform control on the battery controller 20 side sothat the dispersion in SOC of all the cells is in the range of thespecified value.

In the charge/discharge state, a vehicle is in motion and thus the highvoltage battery is charged/discharged. In a charged state, a part of thecharge current is heat-consumed in the capacity adjusting resistors R1and the charge current value of a cell having a high voltage (in whichdispersion occurred) becomes small. In a discharged state, similarly,the discharge current is heat-consumed in the capacity adjustingresistors R1 and the discharge current value of a cell having a highvoltage becomes large. As a result, the voltage of a cell having a highvoltage gets close to the voltages of other cells.

Upon reception of the capacity adjusting command from the MPU, each ICstores command data in a register, and by sending the same command to alower order IC, the instruction is returned to the MPU. This method isthe same as the above-described one. The logic circuit 103 of each ICdecrypts this capacity adjusting command, and judges whether a cellunder the control of the logic circuit is a capacity adjustment targetcell or not from the identifier field. When negation is judged, thelogic circuit takes it as an instruction issued for another IC and doesnot respond, but when affirmation is judged, the logic circuit executescapacity adjustment of the capacity adjustment target cell during acapacity adjustment time instructed in the data field. Specifically, forexample when the cell B2 is the capacity adjustment target cell, theswitch control circuit 102 of the IC-1A outputs a high-level signal tothe switch element SW2 arranged between the BR2 terminal and the CV3terminal (refer to FIG. 11) during the instructed capacity adjustmenttime. The MPU similarly instructs the IC-1A to IC-12A regarding othercells which need capacity adjustment to allow the IC-1A to IC-12A toeliminate dispersion in SOC between the cells B1 to B48. Aftercompleting capacity adjustment of cells under their own control, theIC-1A to IC-12A transmits the completion to (the LIN1 terminal of) thelower-order IC via the LIN2 terminal, and thereby the MPU can recognizethat the capacity adjustment of all the capacity adjustment target cellsis completed.

(Effects and so on)

Although there are parts overlapping with the above explanation sincethe characteristics and effects which the power supply system 1 of thisembodiment has are described in the above explanation, effects and so onof the power supply system 1 will be explained again in an organizedmanner.

Since the power supply system 1 of this embodiment includes the DC/DCconverter in the converter box 21 to supply power to (or receive powerfrom) the inverter device 120 (refer to FIG. 17), essentially it can beaffected easily by noise from the chopper circuit of the DC/DC converterand the inverter of the inverter device 120. Specifically, the DC/DCconverter affects the ICs of the C/C 80 via a constant voltage powergenerating circuit of 5 V or the like of the battery controller, and theinverter device 120 superposes noise on the high voltage battery via thehigh voltage cables 81, 82. Also, since the 48 cells are connected inseries (refer to FIG. 10), the C/C 80 can be affected easily by noisedue to a voltage variation. Even in such a harsh environment, the powersupply system 1 (battery controller 20, C/C 80) is required to operatestable and precisely.

On the battery controller 20 side, as measures for this, the capacitorsC_(N), C_(P), are interposed between the positive and the negativeelectrode of the high voltage battery and the case ground, respectively.This ground is the same potential as the minus side of the 12 V powerconverted by the DC/DC converter (also the same potential as the chassisof the hybrid vehicle). Noise is attenuated by the capacitors C_(N),C_(P), and the battery controller 20 operates stably.

On the other hand, in the C/C 80, only with interposition of thecapacitors C_(N), C_(P), it is difficult to eliminate influence of noiseof the above-described DC/DC converter and the inverter device 120 aswell as influence of noise due to a voltage variation of the highvoltage battery for ensuring a stable and precise operation. In thisembodiment, as shown in the table 1, various noise and surge measuresare implemented. Thus, even when noise due to a voltage variation andnoise from the outside are superposed, it is possible to suppress noiseand eliminate influence of surge voltage, and the C/C 80 can operatestably and precisely. Also, the ICs will not be destroyed in themanufacturing processes of the battery module 9 and the power supplysystem 1. Therefore, the power supply system 1 of this embodiment canensure reliability even in the above-described harsh environment.

Also, in the C/C 80, the 24 IC-1A to IC-12B of the same types aremounted on the substrate, and these ICs are aligned and arranged in apredetermined order. For example, they are mounted two by two on therectangular longer sides of the rectangular continuous straight line1-1′ defined on the substrate from the IC-1A, IC-1B on the highestpotential side to the IC-12A, IC-12B on the lowest potential sidecontinuously in order of potential differences of the corresponding cellgroups AB1 to AB12 (refer to FIG. 9). The distances between rectangularshorter sides of the rectangular continuous straight line 1-1′ are thesame in this embodiment. Accordingly, the ICs can be mounted compactlyon the substrate while giving freedom in design of the C/C 80 accordingto the number of cells 10 constituting the battery modules 9, and themounting area can be made small. Thus, the C/C 80 can be reduced incosts.

Further, in the C/C 80, the capacity adjusting resistors R1 constitutingthe capacity adjusting circuit are mounted in a divided manner at fixedregions of the IC, for example, two regions (dashed-line regions nearthe connecting connectors 48, 49 in FIG. 9) separated from therectangular continuous straight line 1-1′. Accordingly, the influence tothe IC-LA to IC-12B of heat generated by the resistors R1 duringcapacity adjustment can be minimized.

Also, in the C/C 80, the photo couplers PH1 to PH5 for performingcommunication in an insulated state with the MPU of the batterycontroller 20 are divided in two and mounted (the chain double-dashedline regions near the connecting connectors 48, 49 in FIG. 9). Inconventional configurations, 6 photo couplers are needed in total. Sincefive photo couplers are sufficient in this embodiment, the substratearea of the C/C 80 is reduced and costs can be reduced.

Also, the C/C 80 relays the led-out lines from the temperature sensorsTH1 to TH4 to the battery controller 20. These led-out lines aregathered integrally on the connector to which the voltage detectinglines 58 of the cell packs 19 are gathered. Therefore, at the time ofassembly, connections are completed just by inserting the six connectorsprovided on the other side of the detection harness 52 in the connectorsof the cell pack, connecting the harness connector on one side of thedetection harness 52 to the connectors 48, 49 of the C/C 80, andconnecting the connector on the tip of the communication harness 50 tothe connector of the battery controller 20. Therefore, connection ofthese led-out lines can be performed integrally with connection of thevoltage detecting lines, and thereby the labor of connection can besaved. Also, since these led-out lines are integrated with the detectionharness 52 and the communication harness 50, there is no fear ofdisconnection or the like in a hybrid vehicle which generates vibration.Further, in this embodiment, since temperature detections are notperformed on the C/C 80 side but performed on the battery controller 20side, it is not needed to mount AD converters on the ICs. Accordingly,the ICs themselves can be suppressed to be small, and hence thesubstrate area of the C/C 80 can be made small.

Therefore, in the battery module 9, since the C/C 80 can be made small,the battery modules 9 can be reduced in size, and cooling spaces(passage for cooling air) for cooling the respective cells needed in thebattery modules 9 can be assured sufficiently, thereby leading toreduction in size of the power supply system 1. In other words, theoriginal performance of the battery can be drawn out, and a volumecapacity density thereof can be increased.

Also, in the battery modules 9 constituting the power supply system 1 ofthis embodiment, lithium secondary cells are used for the cells 10.Accordingly, a volume capacity density higher than that of the nickelhydride secondary cell can be assured for example. Further, sinceamorphous carbon is used as the negative electrode active material, thestate of charge (SOC) of the cells 10 can be grasped with high accuracyby measuring the open circuit voltage (OCV) as described above.Moreover, since lithium manganese complex oxide is used as the positiveelectrode active material, a low-cost cell can be made as compared tothe case that for example lithium cobalt complex oxide is used for thepositive electrode active material because the material is abundant.Thus, costs for the battery module 9 as well as the power supply system1 can be reduced.

Moreover, since the B-group ICs which detect overcharging of therespective cells constituting the high voltage system are madeindependent from the A-group ICs to monitor the cells, reliability canbe placed in an aspect of safety.

Further, in the power supply system 1 of this embodiment, the MPU of thebattery controller 20 performs communication in an electricallynon-insulated state with the ICs of the C/C 80 via the photo couplersPH1 to PH5, and also the total voltage circuit of the battery controller20 is insulated from the high voltage of the high voltage battery by atransformer. Accordingly, there is no fear of causing voltagedestruction, and propagation to the higher controller 110 side byshort-circuit or the like can be prevented.

Also, in the power supply system 1 of this embodiment, two batterymodules 9 are connected in series via the SD switch 6 formaintenance/inspection. Therefore, during maintenance/inspection, safetyfor a worker can be assured by turning the SD switch 6 to an off stateto work thereon. Also, since the SD switch 6 is exposed on the modulecase 9 a, the switch can be turned to an off state in the initial stageof maintenance/inspection before separating the lower container and theupper cover.

Also, in the power supply system 1 of this embodiment, the batterycontroller 20 receives power via the DC/DC converter from the 24 V leadbattery which is an external power supply. Therefore, as compared to thecase of receiving power from a high voltage battery constituted of twobattery modules 9, the self-maintaining ability of battery functions canbe increased. Although the power supply system 1 of this embodimentexhibits a large effect when used as a power supply device mounted in avehicle, the power supply system 1 can be mounted in various types ofmobile bodies since it includes the DC/DC converter and has certaineffects. Note that in our country, 24 V lead batteries are adopted aspower supply in many trucks.

Also, the power supply system 1 of this embodiment has the positiveelectrode side main relay RL_(P) and the negative electrode side mainrelay RL_(N) inside the relay case 18. Therefore, safety for the entireexternal apparatus can be increased in case that some external forcesact on the power supply system 1 to break part of the power supplysystem 1. Further, since these high voltage relays control relays by acontrol signal from the inverter device 120 which receives power fromthe power supply system 1, safety thereof improves.

For example, in FIG. 17, before the inverter device 120 startsoperation, for example when the vehicle is parked in a parking area orthe like, the charge of the capacitor 128 is kept in a discharged statefor safety. In conjunction with manipulation of the key of the vehicle,it is conceivable to improve safety by discharging the charge of thecapacitor 128 when the key is removed. Next, when the manipulation ofthe key of the vehicle is performed again, the power supply system 1starts supplying direct current power to the inverter device 120. Sincelarge current flows in the input part of the inverter device 120 and thepower supply system 1, electrical resistance in a power supply path issuppressed to be small. Accordingly, it is possible that a large currenttemporarily flows through the capacitor 128 when the power supply system1 and the inverter device 120 are connected. There is a fear that therelays are damaged by this large current, and also there is a fear thatthe direct current terminals of the inverter device or the terminals ofthe capacitor 128 are damaged. In the above-described embodiment, by aninstruction from the MCU 122 that is a control device of the inverterdevice 120, the relay RL_(PRE) is made to conduct prior to the relayRL_(P) so as to supply a current for charging the capacitor 128 via theresistor R_(PRE) for limiting a current. When charging of the capacitor128 proceeds and in a state that the terminal voltage is higher than apredetermined value, the relay PL_(P) is made to conduct and a statethat a direct current can be supplied to the inverter device 120 iscreated. With such a structure and control, the relay RL_(P) of thepower supply system 1 can be protected against adverse effects of alarge current. Also, the direct current terminals of the inverter device120 and the terminals of the capacitor 128 can be protected againstadverse effects of a large current.

A sequence of the prior charging operations of the capacitor 128 may beperformed by the higher controller 110, but when it is performed by aninstruction not from the higher controller 110 but from the MCU 122, acontrol load on the higher controller 110 which is busy in controlling astart up of the vehicle can be reduced. Also, since the MCU 122 isprovided in the same device as the capacitor 128, and is retained in aposition where it is easy to detect the state of charge of the capacitor128, it is possible to avoid complication of the entire system by addingthe above function. For example, by allowing the MCU 122 to control boththe discharging operation of the capacitor 128 and the above-describedprior charging operation, charging and discharging of the capacitor 128can be controlled without complicating the entire driving system of FIG.17, thereby improving safety and reliability.

As described above, in the relay case 18, the precharge relay RL_(PRE)having a small current resistance value than the positive electrode sidemain relay RL_(P) is connected to the positive electrode side main relayRL_(P) in parallel via the resistor R_(PRE), and at an initial time whenthe battery module 9 supplies power to the inverter device 120, theprecharge relay RL_(PRE) is controlled by the inverter device 120 to anon state to thereby charge the smoothing capacitor in the inverterdevice 120. Thus, it is possible to prevent an accident of fusing thepositive electrode side main relay RL_(P) and the negative electrodeside main relay RL_(N) even when the resistance on the input side of theinverter device 120 is small.

Moreover, in the power supply system 1 in this embodiment, the externalcase of the battery module 9 is made in a substantially hexahedron withthe lower cover 45 having three faces of a front face, a bottom face,and a back face, the upper cover 46 having three faces of a left sideface, a top face, and a right side face, and the lower cover 45 and theupper cover 46 being coupled. Accordingly, since spaces of the left sideface and the right side face are open, workability (assemblyperformance) can be improved when two cell pack blocks 40 eachconstituted of six cell packs 19 are arranged on and fixed to the lowercover 45. Safety can be improved also when the lower cover 45 and theupper cover 46 are coupled since visual confirmation from the front faceand the back face direction can be done. Also, since both the uppercover 46 and the lower cover 45 have three faces, costs can be reducedmore than by the external case of a box structure having five faces.

Also, the power supply system 1 of this embodiment can be assembled stepby step: the cells 10→the cell packs 19→(cell pack blocks 40)→thebattery modules 9→the power supply system 1. Therefore, management ofassembly units is easy. Also, since most of connections of the lowvoltage circuit are done with connectors, the connections are easy andmiss wiring can be prevented, and also disconnection due to vibration orthe like can be prevented when being mounted in a hybrid vehicle.

Also, in the battery module 9, the lower cover 45 forms the ducts 75 forthe respective arranged cell packs 19, and the ventilation holes 76 areformed in the ducts 75 at positions corresponding to the spaces betweenthe cells 10 constituting the cell packs 19. Thus, a structure is madein which cooling air blow upward from the lower side between therespective cells 10, and since the cooling air flowing through the ducts75 has a constant temperature, the air having the constant temperatureis blown to the respective cells 10, resulting in an almost constantcooling condition. Also, it becomes a very efficient structure in whichthe cooling system is completed by just forming the cell pack blocks 40,in which the cell packs 19 having the same shapes and the louverfunctions (arch-shape louver 36, cross-shape louver 37) inside arefixed, on the lower cover 45 having the ducts 75 and the ventilationholes 76. The louver shape does not need to be changed for each of thecells 10, and thereby simple assembly becomes possible. Further, theopening areas of the ventilation holes 76 are large on the introducingside of the cooling air and become small with distance toward thedischarging side. Substantially halves of the ventilation holes whichare closest to the introducing side are covered by the blocking louvers77, and the ventilation holes which are closest to the discharging sidehave substantially the same opening areas as the ventilation holes whichare closest to the introducing side. Accordingly, temperatures of thecells 10 can be almost constant.

Then, in the battery modules 9, the lower cover 45 has the lower coverprojections 73 on the bottom face (refer to FIG. 6), and the upper coverrecesses 89 are formed in the upper cover 46. Thus, it becomes possibleto arrange the battery modules 9 in a stacking manner by engaging thelower cover projections 73 with the upper cover recesses 89.Accordingly, the power supply system 1 of this embodiment allowsthree-dimensional arrangement as compared to a planar arrangement of thebattery module 9, thereby improving the spatial use ratio. Here, due tothe structure of fixing with the collars 91 and the long bolts 92,influences of vibration or the like can be eliminated even when beingmounted in a mobile body such as a hybrid vehicle.

Note that in this embodiment, the largeness of the effects of theinductors L, L′ is explained related to the noise measures of the C/C80, but as explained in the item 4 of the table 1, it is also possibleto improve noise resistance of the ICs regarding the resistors R3.

Therefore, “a cell controller in which, for detecting voltages ofrespective cells of a serially connected body of cells constituted byfurther connecting a plurality of groups of cells in series, each of thegroups being constituted of a plurality of cells connected in series, aplurality of ICs each having a voltage detecting circuit are arrangedcorresponding to the groups of cells, each of the ICs is provided with avoltage input terminal for receiving terminal voltages of cellsconstituting a corresponding group, an information reception terminalfor receiving information from an IC corresponding to an adjacent groupof cells, and an information transmission terminal which outputsinformation to an IC corresponding to an adjacent group of cells, therespective ICs corresponding to the groups in an association in order ofpotentials of cells constituting the respective groups constitute a loopinformation transmission path, and the information transmission terminalof an IC corresponding to one of the adjacent groups and the informationreception terminal of an IC corresponding to the other one of theadjacent groups are connected via a resistor for transmitting/receivinginformation via the information transmission path.” can also be includedin the claims. Note that in the above-described embodiment, informationis transmitted toward an IC corresponding to a group with a lowervoltage from an IC corresponding to a group with a higher voltage, butit may be the inverse thereof. Adjacent groups have a relatively smallpotential difference therebetween, and hence information can betransmitted. Although terminal voltages of lithium secondary cellschange by charge/discharge states thereof, reference potentials of theICs corresponding respectively thereto change relatively whentransmission of information is performed between the adjacent groups ofcells, and the potential difference remains in a predetermined range.Thus, the transmission of information is easy, and high reliability canbe maintained.

Also, as explained in the items 5, 6 of the table 1, it is possible toimprove surge resistance or the like of the ICs regarding the schottkydiodes D3, D4.

Therefore, “a cell controller including a plurality of ICs correspondingto groups of cells and each having a voltage detecting unit whichdetects voltages of respective cells in groups of cells in which an evennumber of cells are connected in series, in which each of the ICs has amid-point voltage detecting terminal for detecting a voltage of amid-point of the groups of cells, and a first schottky diode isinterposed between the mid-point voltage detecting terminal and the GNDterminal of each of the ICs.” and “a cell controller including aplurality of ICs corresponding to groups of cells and each having avoltage detecting unit which detects voltages of respective cells ingroups of cells in which an even number of cells are connected inseries, in which each of the ICs has a mid-point voltage detectingterminal for detecting a voltage of a mid-point of the groups of cells,and a first schottky diode is interposed between the mid-point voltagedetecting terminal and the GND terminal of each of the ICs and a secondschottky diode is interposed between a Vcc terminal and the mid-pointvoltage detecting terminal of each of the ICs.” can also be included inthe claims.

Further, in this embodiment, an example is shown in which the switchelements for connecting the capacity adjusting resistors R1 to the cellsin parallel are provided in the ICs. Although this way is quiteexcellent, the present invention is not limited to this, and the switchelements may be provided outside the ICs.

Also, in this embodiment, an example is shown in which a function todetect overcharging is provided in the B-group ICs, but the presentinvention is not limited to this. For example, overcharging, state ofcharge (SOC), state of health (SOH), or the like may be monitored.Further, in this embodiment, an example is shown in which a voltagedetecting function and a capacity adjusting function for the cells areprovided in the A-group ICs and a overcharging detecting function forthe cells are provided in the B-group ICs, but any two of these threefunctions may be provided in the A-group ICs or the B-group ICs and anyone thereof may be provided in the B-group ICs or the A-group ICs. Inthis case, the A-group ICs and the B-group ICs may be different circuitsaccording to purposes, or may be in a form such that they are the samecircuits but a part of functions is used by a group and a part offunctions is not used. In a case of ASIC, in view of tool costs andrunning costs, it may be at lower costs than a case of manufacturingseveral types of ICs. Also, as described above, the A-group ICs and theB-group ICs may be constituted of one IC chip.

Also, in this embodiment, an example is shown in which a five-bytecommand signal is inputted to the FF reception line (FFON), but thepresent invention is not limited to this. In this embodiment, since theB-group ICs have a single function of monitoring overcharging, they maybe configured to start by a high-level signal. Also, the FF output line(FFOUT) may be arranged to notify overcharging of any one of the cellsto the MPU by a high-level signal. In this manner, since the signal is abinary value (high level or low level), transmission in a daisy-chainnetwork can be made faster, and the MPU can comprehend overchargingfaster, so that measures against overcharging are made quicker andsafety can be improved. In this case, the MPU may be configured to allowthe A-group ICs having a voltage detecting function to measure voltages,and know which cell is overcharged from their results thereafter.

Further, in this embodiment, as shown in FIG. 9, an example is shown inwhich, on the substrate of the C/C 80, the ICs are mounted four by fouron the rectangular longer sides of the rectangular continuous straightline 1-1′ from the IC-LA, IC-1B on the highest potential side to theIC-12A, IC-12B on the lowest potential side continuously in order ofpotential differences of the corresponding groups of cells AB1 to AB12,but the present invention is not limited to this. For example, thenumber of ICs mounted on the rectangular longer sides of the rectangularcontinuous straight line 1-1′ may be different. Such a case is effectivewhen connectors, circular holes for fixing a substrate, and so on mustbe arranged, and also in such a case, the distances between therectangular shorter sides of the rectangular continuous straight line1-1′ may be changed, which assures freedom in design.

Also, in this embodiment, since a hybrid vehicle in our country, ahybrid truck in particular, has the 24 V lead battery mounted therein,the power supply system 1 having the DC/DC converter converting 24 V to12 V is presented an example, but trucks having a 12 V led batterymounted therein are also in widespread use in the United States forexample. In such a case, the DC/DC converter is not necessary, and thepower supply system 1 can be reduced in size.

Also, this embodiment is optimum for automobiles including trucks andpassenger cars, and it is conceivable that an automobile has differentsystems of power supply systems. By having the function of the DC/DCconverter, it becomes possible to have a power supply system of adifferent system. When the rotation speed of the motor 130 increases, aninternal induced voltage increases, which makes it difficult to supply anecessary current. It is conceivable to raise a voltage by the DC/DCconverter to supply power with the raised voltage from the inverter tothe motor. The above-described DC/DC converter can be used for raisingof the supply voltage to the inverter. In this case, terminal voltagesof the high voltage battery is not supplied directly to the capacitor128 but are raised in voltage by the DC/DC converter, and direct currentpower with the raised voltage is supplied to the capacitor 128 and thepower module 126.

Also, in this embodiment, an example is shown in which the temperaturesensors TH1 to TH4 are fixed to the cells on the highest potential sidein the groups AB1, AB2, AB11, AB12 constituted of cells, but since it issufficient if the mean temperature for all the cells constituting thehigh voltage battery can be grasped, the present invention is notlimited to the exemplified form. For example, the temperature sensorsmay be fixed to any cells of any two of the cell packs.

Further, in this embodiment, the power supply system 1 for a hybridvehicle is shown as an example, but the present invention has quite alarge effect when applied to a vehicle. Further, other than a vehicle,the present invention can be applied widely to power supply systemsrequiring charging/discharging of a large current and has certaineffects. Also, in this embodiment, an example of the battery module 9 isshown in which 12 cell packs 19 are arranged in parallel in each ofwhich four cells 10 are connected in series, but the present inventionis not limited to the structure and the connection (serial, parallel) ofthe battery module 9. For example, the number of cells 10 may bechanged, and the number or the arrangement of cell packs 19 may bechanged. Further, in this embodiment, an example is shown in which twobattery modules 9 are stacked vertically and accommodated in theexternal box, but three or more battery modules may be accommodated, oralso a power supply system using one battery module 9 is possible.

However, dividing of the cells B1 to B47 shown in FIG. 10 into batterymodules 9 on the higher potential side and the lower potential side havelarge effects as described above. Further, although there are two groupsin this embodiment, the cells connected in series can be divided inseveral groups to be handled according to potentials, and the connectors48, 49 connected to the C/C 80 can be divided based on potentials asshown in FIG. 9. Voltage differences of cells handled by the respectiveconnectors become small, and the number of connecting pins of theconnectors decreases. An influence of a partial connection state at thetime of connecting or releasing the connectors can be made small.

Also, in this embodiment, cylindrical lithium secondary cells are shownas the cells 10 for example, but the present invention is not limited tothis. For example, the cells 10 may have a prismatic, polygonal shape,and a secondary cell covered by a laminate film may be used. Also, otherthan the lithium secondary cell, another secondary cell such as a nickelhydride secondary cell may be used.

Then, in this embodiment, an example is shown in which the intake 14 andthe exhaust port 15 of a battery module 9 are formed in the lower partsof the end faces on the both sides in the longitudinal directionrespectively, but the present invention is not limited to this. Forexample, when the intake 14 is formed in an upper part of an end face ofthe battery module 9, the flow of cooling air is in a diagonal directionwhen viewed from a side face along the longitudinal direction of thebattery module 9, which can increase the cooling effect. Further, theintake 14 may be formed in a side face along the longitudinal direction.

INDUSTRIAL AVAILABILITY

The present invention provides a cell controller which has excellentproductivity, a battery module having the cell controller, and a powersupply system including the battery module, and hence contributes to themanufacturing and sales of the cell controller, the battery module, andthe power supply system. Thus, the present invention has industrialavailability.

1. A cell controller for controlling a serially connected body of cellsconstituted by connecting a plurality of groups of cells in series, eachof said groups being constituted of a plurality of cells connected inseries, the cell controller comprising a plurality of ICs correspondingto said groups, said plurality of ICs each having a voltage detectingunit for detecting voltages of respective cells constituting saidgroups, a switch control unit for controlling conduction and a blockingoperation of a plurality of switch elements connected in parallel tosaid respective cells via resistors, an information input terminal forinputting control information, an information output terminal foroutputting control information, a power supply terminal, and a referencepotential terminal, said plurality of ICs operating based on powersupplied from said cells constituting said groups to said power supplyterminal and said reference potential terminal; said plurality of ICsdetecting voltages of respective cells by said voltage detecting unitand controlling said plurality of switch elements connected in parallelto said respective cells via resistors by said switch control unit toadjust states of charges of said cells, wherein: among said groupsconnected in series, said information output terminal of one ICcorresponding to one group of adjacent groups and said information inputterminal of the other IC corresponding to the other group of saidadjacent groups are connected electrically; transmission of controlinformation is performed from said information output terminal of saidone IC to said information input terminal of said the other IC; and apower supply terminal of each of said ICs is connected to a positiveelectrode of a higher-order cell among said cells constituting saidcorresponding group via a first inductor.
 2. A cell controller forcontrolling a serially connected body of lithium cells constituted byconnecting a plurality of groups in series, each of said groups beingconstituted of a plurality of lithium cells connected in series,wherein: a plurality of ICs are fixed on a control substratecorresponding to said groups; said plurality of ICs each have a voltagedetecting unit for detecting voltages of respective lithium cellsconstituting said groups, a plurality of switch elements connected inparallel to said respective lithium cells via resistors, a switchcontrol unit for controlling conduction and a blocking operation of saidplurality of switch elements, an information input terminals forinputting control information, an information output terminal foroutputting control information, a power supply terminal, and a referencepotential terminal; said plurality of ICs operate based on powersupplied from said corresponding group to said power supply terminal andsaid reference potential terminal of a corresponding IC; said pluralityof ICs detect voltages of respective cells of a corresponding group bysaid voltage detecting unit and control said plurality of switchelements connected in parallel to said respective cells via resistors bysaid switch control unit to adjust states of charges of said cells; awiring is provided on said control substrate, said wiring electricallyconnecting, among said groups connected in series, said informationoutput terminal of one IC corresponding to one of adjacent groups andsaid information input terminal of the other IC corresponding to theother one of said adjacent groups; power supply terminals of said oneand the other ICs are connected respectively to a positive electrode ofa higher-order cell constituting said corresponding group via a firstinductor; the reference potential terminal of said one IC is connectedvia said first inductor to, together with said power supply terminal ofsaid the other IC, a positive electrode of a higher-order cellconstituting a group to which said the other IC corresponds; and saidfirst inductors are provided on said control substrate respectively. 3.The cell controller according to claim 2, wherein a second inductor isinterposed between a negative electrode of a lowest-order cell among aplurality of cells constituting a lowest-order group among said groupsconnected in series and a reference potential terminal of saidlowest-order group.
 4. The cell controller according to claim 1, whereina first Zener diode is interposed between the power supply terminal andthe reference potential terminal of each of said ICs.
 5. The cellcontroller according to claim 4, wherein a second Zener diode isinterposed between the information input terminal and the referencepotential terminal of each of said ICs.
 6. The cell controller accordingto claim 1, wherein the information output terminal of said first IC isconnected to the information input terminal of said second IC via aresistor.
 7. The cell controller according to claim 1, wherein saidgroups are each constituted of an even number of cells, each of said ICshas a mid-point voltage detecting terminal for detecting a voltage of amid-point of said groups, and a first schottky diode is interposedbetween the mid-point voltage detecting terminal and the referencepotential terminal of each of said ICs.
 8. The cell controller accordingto claim 7, wherein a second schottky diode is further interposedbetween the power supply terminal and the mid-point voltage detectingterminal of each of said ICs.
 9. The cell controller according to claim2, wherein a first Zener diode is interposed between the power supplyterminal and the reference potential terminal of each of said ICs. 10.The cell controller according to claim 9, wherein a second Zener diodeis interposed between the information input terminal and the referencepotential terminal of each of said ICs.
 11. The cell controlleraccording to claim 2, wherein the information output terminal of saidfirst IC is connected to the information input terminal of said secondIC via a resistor.
 12. The cell controller according to claim 2, whereinsaid groups are each constituted of an even number of cells, each ofsaid ICs has a mid-point voltage detecting terminal for detecting avoltage of a mid-point of said groups, and a first schottky diode isinterposed between the mid-point voltage detecting terminal and thereference potential terminal of each of said ICs.
 13. The cellcontroller according to claim 12, wherein a second schottky diode isfurther interposed between the power supply terminal and the mid-pointvoltage detecting terminal of each of said ICs.
 14. A cell controller,comprising: a control substrate; connectors provided on said controlsubstrate for electrically connecting to respective terminals of aserially connected body of lithium cells constituted by connecting aplurality of groups in series, each of said groups being constituted ofa plurality of lithium cells connected in series; a plurality of ICsprovided on said control substrate corresponding to said groups, saidplurality of ICs each having a voltage detecting unit for detectingvoltages of respective lithium cells constituting said groups, aplurality of switch elements connected in parallel to said respectivelithium cells via resistors, a switch control unit for controllingconduction and a blocking operation of said plurality of switchelements, an information input terminals for inputting controlinformation, an information output terminal for outputting controlinformation, a power supply terminal, and a reference potentialterminal, said plurality of ICs operating based on power supplied fromsaid corresponding group to said power supply terminal and saidreference potential terminal of a corresponding IC, and said pluralityof ICs detecting voltages of respective cells of a corresponding groupby said voltage detecting unit and controlling said plurality of switchelements connected in parallel to said respective cells via resistors bysaid switch control unit to adjust states of charges of said cells; afirst wiring provided on said control substrate, said first wiringelectrically connecting, among said groups connected in series, saidinformation output terminal of one IC corresponding to one of adjacentgroups and said information input terminal of the other IC correspondingto the other one of said adjacent groups; a plurality of first inductorsprovided on said control substrate and connected electrically betweenrespective power supply terminals of said one and the other ICs andpositive electrodes of higher-order cells to which said one and theother ICs correspond respectively; a second wiring provided on saidcontrol substrate for a reference potential terminal of said one IC tobe connected via said first inductor to, together with said power supplyterminal of said the other IC, a positive electrode of a higher-ordercell to which said the other IC corresponds; and a first capacitorprovided on said control substrate to be connected to said respectivelithium cells in parallel respectively.
 15. The cell controlleraccording to claim 14, wherein a second capacitor having a capacitylarger than said first capacitor is provided on said control substrate,said second capacitor connected between a power supply terminal and areference potential terminal of each of said ICs.
 16. The cellcontroller according to claim 14, wherein each of said ICs furthercomprising a state monitoring unit which monitors states of cells ofsaid corresponding group.
 17. The cell controller according to claim 16,wherein said state monitoring unit monitors overcharging of saidrespective cells.
 18. The cell controller according to claim 16, whereinany two of said voltage detecting unit, said switch control unit andsaid state monitoring unit are accommodated in a first chip and any onethereof is provided in a second chip, said second chip being connectedin parallel to said first chip.
 19. The cell controller according toclaim 18, wherein said first and second chips each have said informationinput terminal and said information output terminal, said informationoutput terminal of said first chip is connected to said informationinput terminal of said lower-order first chip via a resistor, and saidinformation input terminal of said second chip is connected to saidinformation input terminal of said lower-order second chip via aresistor.
 20. The cell controller according to claim 19, wherein asecond Zener diode is interposed between said information inputterminals and reference potential terminals of said first and secondchips.
 21. The cell controller according to claim 19, further comprisinga plurality of photo couplers for communicating with a higher-ordercontrol device in an electrically insulated state, wherein saidinformation input terminals of said highest-order first and second shipsare connected to a photo coupler on a receiving side via a resistor, andsaid information output terminals of said lowest-order first and secondchips are connected to a photo coupler on a receiving side via aresistor.
 22. The cell controller according to claim 18, wherein saidfirst and second chips are constituted of a same circuit.
 23. A batterymodule, comprising: a module having at least one group in which aplurality of cells are connected in series; and the cell controlleraccording to claim
 1. 24. A battery module, comprising: a module havingat least one group in which a plurality of cells are connected inseries; and the cell controller according to claim
 2. 25. A batterymodule, comprising: a module having at least one group in which aplurality of cells are connected in series; and the cell controlleraccording to claim
 14. 26. A power supply system, comprising: ahigh-voltage battery having at least one battery module according toclaim 23; and a battery controller which communicates with said cellcontroller in an electrically insulated state and calculates, fromreceived voltages of all cells constituting said high voltage battery,states of cells of all the cells.
 27. A power supply system, comprising:a high-voltage battery having at least one battery module according toclaim 24; and a battery controller which communicates with said cellcontroller in an electrically insulated state and calculates, fromreceived voltages of all cells constituting said high voltage battery,states of cells of all the cells.
 28. A power supply system, comprising:a high-voltage battery having at least one battery module according toclaim 25; and a battery controller which communicates with said cellcontroller in an electrically insulated state and calculates, fromreceived voltages of all cells constituting said high voltage battery,states of cells of all the cells.
 29. The power supply system accordingto claim 26, wherein capacitors intervene between a positive electrodeof said high voltage battery and a ground and between a negativeelectrode thereof and the ground, respectively.
 30. The power supplysystem according to claim 27, wherein capacitors intervene between apositive electrode of said high voltage battery and a ground and betweena negative electrode thereof and the ground, respectively.
 31. The powersupply system according to claim 28, wherein capacitors intervenebetween a positive electrode of said high voltage battery and a groundand between a negative electrode thereof and the ground, respectively.